Biostratigraphy of the Akiyoshi Limestone Group,

Bull. Kitakyusku Mus. Nat. Hist., 16: 1-97. March 28, 1997 

Middle Carboniferous and Lower Permian Fusulinacean 

Biostratigraphy of the Akiyoshi Limestone Group, 

Southwest Japan. Part I 

Yasuhiro Ota 

Department of Earth and Planetary Sciences, Faculty of Science, 

Kyushu University33, Hakozaki, Fukuoka 812,Japan 

(Received October 31, 1996) 

Abstract The Akiyoshi Limestone Group, oneof the most representative stratigraphic 

standards ofJapanese Carboniferous and Permian, is widely distributedin the Akiyoshi 

Terrane, Southwest Japan. 

TheJigoku-dani area, the main area for investigation, is located in the northwestern 

part of the Akiyoshi Plateau, where the Middle Carboniferous and Lower Permian 

limestones are widely exposed. They are mainly composed of micritic limestones, 

indicating a lagoonal facies, in the relatively low energy environments within the 

Akiyoshi organicreefcomplex. The limestones are alsocharacterized by abundant and 

well-preserved fusulinaccans, and the following nine zones including seven subzones, 

were recognized in ascending order as: 1. Fusulinella biconica Zone, 2. Fusulina cf. 

shikokuensis Zone: 2-1. Fusulinella cf. obesa Subzone, 2-2. Pseudofusulitulla hidaensis 

Subzone, 3. Obsoletes obsolelus Zone: 3-1. Protriticites toriyamai Subzone, 3-2. Protriticites 

matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayamadakensis Zone: 5-1. 

Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconicus Subzone, 

6. Schwagerina () cf. satoi Zone, 7. Pseudoschwagerina muongthensis Zone, 8. Pseudqfusulina 

vulgaris globosa Zone, 9. Pseudofusulina afi". ambigua Zone. The distribution of these 

fusulinacean zones shows well the inverted structure of limestones in this area. 

The second investigated AK area is located in front of the Akiyoshi-dai Museum of 

Natural History, where limestones with nearly complete successions of the Middle 

Carboniferous to Lower Permian are well exposed. The following fusulinacean zones 

are discriminated alonga measured traverse, in ascending order:Pseudofusulinella hidaensis 

Zone, Protriticites matsumotoi Zone (s. I.), Montiparus sp. A Zone, Triticites simplex Zone (s. 

1.), Pseudoschwagerina muongthensis Zone, and Pseudofusulina vulgaris Zone. Of them, 

Protriticites matsumotoi Zone (s. I.) is tentatively subdivided into the lower Protriticites 

matsumotoi Zone (s. s.) and the upper Quasifusulinoides sp. A Zone. Triticites simplex Zone 

(s. 1.) is tentatively subdivided into the lower Schwagerina sp. A Zone and the upper 

Triticites simplex Zone (s. s.). Limestones in this area mainly consist of alternation of 

micritic limestones and those with sparry calcite matrices. The facies of limestones 

indicate that they represent a marginal lagoon paleocnvironment. The limestones in 

this area explain the two sequences. 

The third investigated area, Mt. Maruyama, contains Middle and Upper Carbo 

niferous limestones. They represent a sedimentary environment of reef flat or bypass 

margin between the fore reef and open sea. They yield the primitive types ofthegenus 

Protriticites, i.e., Protriticites yanagidai Ota, Protriticites masamichii Ota, and Protriticites

Yasuhiro Ota 

toriyamai Ota. From viewpoints of their morphological characters and affinities, 

Protriticites yanagidai Ota represents a primitive stage in the phylogenetic line between 

Protriticites yanagidai Ota and Protriticites matsumotoi (Kanmera), whereas Protriticites 

masamichii Ota is likely to be a transitional species to Montiparus matsumotoi injlatus, 

reported by Watanabe (1991). 

Based on these fusulinacean assemblages and phylogenetic considerations, it is 

concluded that the variation of elements among fusulinacean assemblages is caused by 

change of lithofacies in development of the Akiyoshi organic reef complex. It has a 

large influence in recognition of the biostratigraphic units. The palcoenvironmental 

analysis of the Akiyoshi organic reef complex is indispensable for establishment of the 

reexamined biostratigraphy. 

Introduction 

The study area is located in the Akiyoshi Terrane of Southwest Japan where the 

Middle Carboniferous to Lower Permian Akiyoshi Limestone Group is widely dis 

tributed. The Akiyoshi Limestone Group which contains well-preserved fusulinaceans 

and many other well-preserved mega-fossils is considered to have originally 

formed as an organic reef complex upon a basaltic mound. This paper describes the 

fusulinacean faunas and discusses the elements of the newly discriminated fusulina 

cean zones. It also examines the Middle Carboniferous to Early Permian fusulina 

cean phylogenetic transition in the Jigoku-dani area and two other related areas on 

the Akiyoshi limestone plateau. 

The principal survey area, Jigoku-dani, is located in the northwestern part of the 

Akiyoshi Plateau. Karst topography characterized by lapie field, is well developed 

and a valley with a NE-SW trend is located in the middle of the area. Middle Car 

boniferous to Lower Permian limestones with a number of well-preserved fusulinaceans, 

are widely distributed. Consequently, this area was first selected for the ex 

amination of the transition of the fusulinacean assemblages during Middle Carbo 

niferous to Early Permian. M. Ota (1977) suggested that the general strikes and 

dips of the Akiyoshi Limestone Group in the area are nearly horizontal. The author 

set a starting point at an altitude of 355 m, and carried out field observation and 

sampling of materials with a measuring tape. The measured traverses (JI Traverse) 

were mainly drawn by crossing the general trend of the strike and sometimes drawn 

by lines parallel to strike. Limestone samples were carefully collected along the 

measured traverses. 

The second investigated AK area was selected in front of the Akiyoshi-dai Muse 

um of Natural History. In this area, there are nearly complete successions of Car 

boniferous to Lower Permian limestones with abundant fusulinaceans. 

also characterized by a lapie field. 

This area is 

The third investigated area, Mt. Maruyama is located in the Isa Quarry, Mine 

City. A principal traverse was set and measured along the eastern slope of Mt.

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 3 

Maruyama at an elevation of about 200 m with the following abbreviation as MA 

Traverse. This traverse was established by crossing the general strike of E-W trend 

at right angles. Limestones in this area are variable in their organic composition 

with rugose corals, ammonoids, phylloid algae, brachiopods and fusulinaceans occur 

ring alone or together. The lithologic facies of limestones and their fossil compo 

nents suggest that the paleoenvironment of this area was a reef flat or bypass margin 

between the fore reef part of the Akiyoshi organic reef complex and open sea (Fig. 1). 

m 1 ; 

Fig. 1. Simplified geologic map of the Akiyoshi area, showing locations of the investigation 

areas, Jigoku-dani area, AK area and Mt. Maruyama area. 1. Akiyoshi Limestone 

Group. 2. Beppu and Ota Groups. 3. Tsuncmori Group. 4. Cretaceous sedimentary 

and igneous rocks. 5. Major thrust.

Yasuhiro Ota 

Historical review 

-I. Geology of the Akiyoshi Limestone 

The geology of the Akiyoshi Limestone and surrounding areas was first investi 

gated by Ozawa (1923), who established the biostratigraphy by the use of fusulina 

cean zones. 

He discovered the inverted succession of the fusulinacean zones and 

recognized the inverted sequences as an autochthonous recumbent fold caused by lat 

eral movement from south to north. Ozawa's interpretation was developed by 

Kobayashi (1935) and he proposed the Akiyoshi Phase for the first of the Mesozoic 

orogenic movements. Toriyama (1954a, b, 1958) reexamined the geology and 

fusulinacean paleontology of the Akiyoshi Limestone Group and the surrounding 

non-calcareous sedimentary rocks. He studied the Carboniferous and Permian 

fusulinaceans in detail and established refined fusulinacean zones on the Carbonif 

erous and Permian limestones. The fusulinacean zones by Toriyama (1963, 1967, 

1978) had been treated as a standard of the Carboniferous and Permian biostratigra 

phy in Japan. Along with the biostratigraphic work, Toriyama showed his interpre 

tation on the geologic structure of the Akiyoshi Limestone Group. Later, Hasegawa 

(1958, 1963) and Murata (1961) showed different interpretations on the inverted 

structure of the Akiyoshi Limestone Group. 

Concurrently, a sedimentological study with the biostratigraphy, for the purpose 

of the paleoenvironmental examination had been started by M. Ota and others. 

Eto (1967) examined the bio- and lithofacies of the lower part of the Akiyoshi 

Limestone Group in the Okubo area. He analyzed biofacies of limestones and re 

constructed the sediment depositional process of limestones on the volcanic seamount. 

In 1968, M. Ota first suggested for the paleoenvironments of the Akiyoshi 

Limestone Group that it was formed as an organic reef complex on the basaltic seamount 

like an atoll of the present ocean. This is an epoch-making study from the 

viewpoint of paleoenvironmental analysis on the Akiyoshi Limestone Group. The 

detailed lithology of the basal pyroclastic rocks was examined and described by 

Yanagida, M. Ota, Sugimura and Haikawa (1971). They showed the sedimentary 

sequence of the Akiyoshi Limestone in the Shishide-dai area with a columnar section 

and description of the biostratigraphy of the lowest part of the Akiyoshi Limestone 

Group. Schwan and M. Ota (1977) carefully reexamined the geologic structures of 

the Akiyoshi Limestone Group and surrounding non-calcareous rocks. They sug 

gested lateral and rotating pressures caused by gravity movement for the partly in 

verted succession of the Akiyoshi Limestone Group. 

The new interpretation for the tectonics of limestones and the surrounding noncalcareous 

rocks, based on the plate tectonic theory of the new global tectonics, was 

shown by Kanmera and Nishi (1983) and Sano and Kanmera (1988). They con 

sidered that the Akiyoshi organic reef was developed on a seamount of basaltic rock 

and then accreted to the terrigenous sediments of the Permian Tsunemori Formation


at the end of the Middle Permian. 

The following palaeontological and geological contributions are important for 

establishment of the biostratigraphy and comprehension of the accretionary process 

of the Akiyoshi Limestone Group: Fujii (1972); Fujii and Mikami (1970); Haikawa 

(1986, 1988); Haikawa and M. Ota (1978, 1983); Hasegawa (1967); Hashimoto 

(1979); Ichikawa (1984, 1990); Kawano (1960); Kimura, Hayami and Yoshida 

(1991); Matsusue (1986, 1988); Miura (1987); Nakamura and M. Ota (1974); 

Nishida (1971); Nishida and Kyuma (1982, 1984); M. Ota (1971); M. Ota, 

Toriyama, Sugimura and Haikawa (1973); N. Ota, Sugimura and M. Ota (1969); 

Sakagami (1964a, b); Sakagami and Sugimura (1978, 1983); Sano, Iijima and 

Hattori (1987); Sano and Kanmera (1991a, b, c, d); Sugimura (1972, 1974, 1985); 

Sugimura and M. Ota (1971, 1980); Sugiyama (1984); Uchiyama, Sano and 

Kanmera (1986); Ueno (1991a, b, c); Yanagida (1962, 1965, 1968, 1973, 1979, 

1983); Yanagida, M. Ota and Nagai (1977); Yamagiwa and M. Ota (1963). 

-II. Middle Carboniferous to Lower Permian biostratigraphic units in the 

Akiyoshi Limestone Group 

The fusulinacean biostratigraphy of the Akiyoshi Limestone Group has been 

treated as a standard of the Japanese Carboniferous and Permian. Recently, the 

chronostratigraphic units of the Middle Carboniferous and Lower Permian have been 

very often discussed in the world to confirm the exact boundary between the Carbon 

iferous and Permian. The Middle Carboniferous to Lower Permian biostratigraphic 

units in the Akiyoshi Limestone Group also have been discussed by many workers, 

such as, Ozawa (1923), Kobayashi (1935, 1941), Sugiyama (1939), Toriyama 

(1954a, b), Hasegawa (1958, 1963, 1988), Murata (1961), M. Ota (1968, 1977), 

Ueno (1989), Ishii (1990), Ozawa and Kobayashi (1990), Watanabe (1991), and 

Y. Ota and M. Ota (1993). 

In case of the Akiyoshi region, it is well known that the Akiyoshi Limestone 

Group was formed as an organic reef complex and that there is a great variation in 

the biofacies and lithofacies. Consequently, in the Akiyoshi Limestone, the fusulina 

cean assemblages of the same age often show different constituents with different types 

of the limestone, suggesting different paleoenvironments (M. Ota, 1977). Therefore, 

it is indispensable to carefully discern the paleoenvironment in the Akiyoshi organic 

reef complex to establish the standard fusulinacean zones in the Akiyoshi Limestone 

Group. A number of stratigraphic units of the same age with different leading fossils 

are known in the Akiyoshi Limestone Group. It is understood that the complicated 

state ofzonation might be caused by differences of the original habitats of biota in the 

organic reef complex. For instance, Ozawa and Kobayashi (1990) proposed 47 

fossil zones in the Akiyoshi Limestone Group. However, these zones are generally 

not mappable and some fossils are not included in these zones (e.g. Sugiyama and 

Haikawa, 1993). These finely distinguished zones, appear to be reasonable, how-

6 Yasuhiro Ota 

ever they are sometimes not practical. A careful examination of the lateral and 

vertical distributions and transitions in the biofacies and lithofacies is required so as 

not to disregard the original habitats of biota in the various types of limestones. 

Watanabe (1991) discussed the inflated schwagerinids and proposed some phy 

logenetic lineages and datum levels among them. His proposals are very interesting 

and logical. The inflated schwagerinids are well known in world wide distribution. 

Therefore they are very useful for international correlation. For establishing the 

chronostratigraphic units, the reconstruction of the evolutionary trend of the inflated 

schwagerinids is indispensable. On the other hand, the inflated schwagerinids are 

also known to occur in specialized environments of deposition, that show apparently 

imbalanced distribution of them, near the Carboniferous and Permian boundary 

(Ross, 1964). Therefore, special attention and examination of the constituents of the 

inflated schwagerinids are essential to establish the standard of both logical and 

practical chronostratigraphic units in the local area. Details of examination and 

comparison of the biostratigraphic units are discussed in the following chapters. 

Research on the chronostratigraphic units near the 

Carboniferous-Permian boundary 

The chronostratigraphic divisions of the Carboniferous and Permian have been 

discussed for many years in and outside Japan. The definition ofthe Carboniferous- 

Permian boundary has received special attention. As the Carboniferous-Permian 

boundary is an intersystem boundary, defining the boundary means to establish the 

datum position in the rock sequences and this is essential for worldwide correlation. 

The name Carboniferous was derived from the coal bearing beds (Coal Mea 

sures) in England, whereas that of the Permian originated from the region of Perm, 

Russia. The Upper Carboniferous in England is mainly composed of terrigenous 

sediments. The Lower Permian in Russia, on the other hand, mainly comprises ma 

rine sediments. Therefore, it is not easy to confirm the boundary between the Car 

boniferous and Permian and to make intercontinental correlations of the Upper 

Carboniferous to Lower Permian successions. In general the Carboniferous-Per 

mian boundary is defined by marine sediments and fossils, which should be effective 

for the world wide correlation. From historical view points, the boundary should be 

defined in Russia. However, the Carboniferous and Permian boundary has been left 

ambiguously even in the type area. Therefore, it is true that many workers continue 

to apply their own definition. 

Here, careful considerations are summarized in three cases, relating to the 

boundary problems. 

(1). The first case is the incompatibility caused by treating the stratigraphic 

boundary as the chronostratigraphic boundary. This consideration has resulted 

from regarding faunal elements of different ages as being of the same age.


(2). The second case is the confusion caused by applying the personal defini 

tion of each worker for the Carboniferous and Permian boundary even in Russia. 

This trouble is also due to a key fossil which was chosen for defining the Carbonifer 

ous-Permian boundary in spite of the inexact state of its taxonomic position. 

(3). The third case is shown by applying the evolutionary stage of a fossil for 

defining the boundary. There are also some problems, because it is difficult to con 

firm the key fossil for defining the Carboniferous-Permian boundary. 

As mentioned above, each case includes complicated and unsolved problems, 

and arguments about the definition of the Carboniferous-Permian boundary have 

continued since Murchison first introduced the Permian in 1841. 

Some proposals are introduced as follows. 

According to Rauser and Shchegolev (1979), the Carboniferous-Permian 

boundary has been studied intensively since Murchison, and the highest stratig 

raphic unit in the Carboniferous, namely, the top of "Schwagerina" Horizon was 

widely recognized as marking of the Carboniferous-Permian boundary. However, 

after the Asselian Stage was established by Ruzhencev, some paleontologists argued 

that the Carboniferous-Permian boundary should lie at the base of the Asselian, 

namely, at the baseof the "Schwagerina" Horizon. Definitions of the boundary of the 

Carboniferous and Permian boundary have been summarized as follows. 

1. Put the boundary between the Carboniferous and Permian at the base of the 

Daixina sokensis Zone of the Gzhelian. 

2. Make the base of the Asselian the boundary between the Carboniferous and 

Permian. 

3. Put the boundary at the base of the upper fusulinacean zone in the Asselian, 

(the base of Nenetsky Horizon). 

4. Place the boundary at the top of the Asselian (Table 1). 

Rui and Zhang (1987) summarized the Carboniferous-Permian boundary in the 

world. According to them, six proposals for the Carboniferous-Permian boundary 

were shown even in Russia as follows. 

1. The Carboniferous-Permian boundary is at the base of the Daixina sokensis 

Zone in the upper part of the Gzhelian Stage. 

2. The base of the Daixina bosbylauensis-Daixina robusla Zone is the Car 

boniferous-Permian boundary. 

3. The basal part of the Asselian Stage in Russia, namely, the Schwagerina 

vulgaris-Schwagerina fusiformis Zone is the lowest part of the Permian. 

4. The basal part of the Schwagerina sphaerica-Pseudofusulina firma Zone of the 

upper part of the Asselian, namely, the lowest part of the Nenet Horizon is the lowest 

part of the Permian. 

5. The Carboniferous-Permian boundary is between the top of the Asselian and 

the base of the Sakmarian, namely, between the Schwagerina sphaerica-Pseudofusulina 

firma Zone and the Pseudofusulina moelleri-Pseudofusulina uralica Zone.

Yasuhiro Ota 

Table 1. 

Correlation of the Carboniferous and Permian boundary among the main pro 

vinces (after Rauser and Shcheoolev, 1979). 

Russian 

Platform &Ural 

Camlc 

Alps 

USA 

W.Texas 

New 

Mexfoo 

Kuma 

Zone 

Formation 

Zone 

si 

1 

m 

Hi 

nil 

ft 

l! 

C3 

ii 

6. The Carboniferous-Permian boundary is at the boundary between the 

Artinskian and Sakmarian (Table 2). 

In USA Beede and Kniker (1924) considered that "Schwagerina" was a good 

index fossil and its earliest occurrence mightbe safely regarded as revealing the basal 

part of the Permian. They proposed that "the zone of Schwagerina" (=Pseudo 

schwagerina of modern usage) should be recognized as the base of the Permian. Ac 

cording to the Permian Subcommittee of the National Research Council's Committee 

on Stratigraphy (Dunbar, Chairman) (1960), the U.S. Geological Survey officially 

recognized the Permian as a system in 1941. But it was uncertain until 1951 wheth 

er the Wolfcampian Series was "Permian". It is common that American geologists 

usually put the base of the Pseudoschwagerina Zone as the base of the Permian. They

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 

Table 2. Different levels proposed for theCarboniferous-Permian boundary in Russia (after 

Rui and Zhang, 1987). 

Official Carboniferous - Permian boundary in Russia 

(Russian Platformand Ural) 

Horizon 

Zone 

Rybakov. 1962 

Lurryak. 1962 

Lever), 1986 

Barkhatova, 

1970 

Raiser. 1960 

RertOnger. 

1969: Koar. 1884 

Movsrtovich. 1S66 

Ruzherchev 

and 

Sarycheva, 

196S 

Irgjn 

Burtsyev 

Parafusulinalutugtni 

Pseudofusulina ccncavutas 

Permian 

Styertttamak 

Pseudofusulina urdalensis 

Pseudofusulina vemeuSi • 

Psf. uraBca 

Pseudofusulina moeBeri 

£ 

Psf. 

moeBeriZ. 

Schwagerina sphaerica - 

Pseudofusulina firma 

Nenet 

Horizon 

Carboniferous 

Sokotiegor 

Schwagerina moelleri• 

Pseudofusulina fecunda 

Schwagerina vulgaris • 

SfusHbrmis 

S. vulgaris. 

S. fusttcnnlsZ. 

Dah&ia 

bosbyt&uoftsls 

D. robust* Z 

Carboniferous 

Carboniferous 

Daixina sokensis 

Daixina 

sokensisZ. 

JiguHtespgulensis 

Carboniferous 

have the opinion that the base of the Permian in the U.S. is essentially equivalent 

to the same horizon of the Russia (Fig. 2). Ross (1984) summarized Carbonifer 

ous-Permian fusulinaceans of North America and concluded that the base of the 

Asselian in the Russian type locality, namely, the base of the zone with large, inflated 

schwagerinids, was presently widely recognized as the base of the lowest Permian 

faunal zone by many invertebrate paleontologists in North America, Japan and south 

ern Europe. Wilde (1984) also published on the Carboniferous-Permian boundary 

and he discussed this problem from the viewpoint of fusulinacean taxonomy. He 

also remarked that the Carboniferous-Permian boundary had been drawn at the base 

of the Asselian Stage in Russia. In addition, he recognized the boundary as equiva 

lent to the middle Wolfcampian unconformity, identified in the type section of the 

Wolfcampian in the United States (Figs. 3, 4). 

In China, Rui and Zhang (1987) reviewed the current situations of the Car 

boniferous-Permian boundary. According to them, before 1970, Chinese workers 

traditionally regarded the top of the Pseudoschwagerina Zone in the Maping (Chuanshan) 

Formation as the upper most of the Carboniferous, and the lower part of the 

Chihsia Formation, namely, the Schwagerina tschernyschewi Zone or the Misellina 

Subzone ofthe Parafusulina Zone as the lower most ofthe Permian. In 1981, Rui Lin 

found the "Carboniferous" (traditional Chinese sense)-Permian mixed fusulinacean


U Jl i t i L ii 

UJ 4 

CD 

c 

a 1- 

1 

co 

z 

Pseudofusulina 

< 

Q. a. 

•V* 

< 

/ 'seudoschif/agerina 

< 

.3 

_i 

§ 

Schubertella 

Schwdgerina 

ir 

ii ,, -J- 

LeptoWffc/tes 

" 

Parasch vagerina 

f 

w 

c 

a 

c 

UJ 

CD 9 o 

< 

r- 

CO 

 

Pseudoi usulinella 

z 

< 

"1 

Dunba inella 

> 5 Tr/fii ;/fes 

>. 

a: V 

CO > 

c 

c 

' f 

a> 

a 

© z 

•9 < 

3 

rr 

O 

CO 

CO 

Eowaeringella 

1 

' 

Fig. 2. Approximate ranges of important fusulinacean genera near the Virgilian-Wolfcam 

pian boundary in the Big Hatchet Mts. (after Wilde, 1984; Rui and Zhang, 1987). 

fauna in the section of the "Carboniferous" to Permian continuous sediments above 

the uppermost Pseudoschwagerina Zone or the Robustoschwagerina schellwieni Zone of 

Permian age. This sequence seems to represent the Liangshan Member, and Rui 

advocated that the lower boundary of the Permian should be placed below this 

limestone sequence. Afterwards, some workers supplemented and revised the 

definition on the traditional boundary. At present 18 main proposals for the 

Chinese Carboniferous-Permian boundary are known (Rui and Zhang, 1987). 

These Chinese proposals have been continuously discussed and they are put into six 

main opinions about the definition of the Carboniferous-Permian boundary (Table 

3). 

1. Putting the boundary between the Carboniferous and Permian at the top of 

Schwagerina Zone, is known as the traditional boundary in China and used for more 

than 40 years. In short, the boundary is compared with the top of the Pseudo 

schwagerina Zone or the Sphaeroschwagerina Zone, namely the top of the Maping 

Formation or the Chuanshan Formation, correlated with the boundary between the

Fig. 3. Correlation of Carboniferous-Permian fusulinid zones between Russia and U. S. A. (after Wilde, 1984). 

c 

Q. 

E 

s 

cr) 

c 

co 

CD 

Q_ 

CD 

Q 

c 

eg 

'c 

CO 

c 

c 

CD 

Q_ 

u. 

0 

Q. 

Q. 

J3_ 

O 

RUSSIA 

U. S. A. 

Robustoschwagerina tumida, Parafusulina 

Pseudofusulina ex gr. vulgaris - kraffti 

11 

Robustoschwagerina stanislavi 

Parafusulina, Skinnerella 

Robustoschwagerina ex gr. tumidiformis 

10 

Pseudoschwagerina 

Chalaroschwagerina, Monodixodina 

CD 

Q_ 

Schwagerina sphaerica 

Preparafusulina 

1CD 

i 

Cuniculinella 

o 

Pseudoschwagerina robusta 

Schwagerina moelleri 

2 

8 

Pseudoschwagerina robusta 

Schwagerina vulgaris - fusiformis 

Pseudoschwagerina uddeni 

Occidentoschwagerina 

Daixina 

Triticites - Schwagerina 

ui 

Jigulites 

Triticites - Schwagerina 

c 

o 

n 

i_ 

CO 

O 

k_ 

CD 

Q. 

Q. 

D 

CD 

Rauserites stuckenbergi 

Triticites 

ohioensis - articus - irregularis 

Montiparus 

Obsoletes - Protriticites 

Triticitesbeedei - moorei - plummeri 

Dunbarinella, Waeringella, Rauserites 

Kansanella 

Triticites ohioensis 

Triticites planus 

Eotriticites 

Eowaeringella


4. Possible alternate correlation offusulinid zones, Russia-USA (after Wilde, 1984). 

Asselian and Sakmarian Stages. 

2. The Carboniferous-Permian boundary should be drawn at the base of the 

Pseudoschwagerina morsei- Robustoschwagerina xiaodushanica Zone, namely, the lowermost 

part of the Mapingian, characterized by the first appearance of the rapidly evolving 

pseudoschwagerinids (Zhou et ai, 1987, Fig.5). 

3. The base of the Montiparus Zone is regarded as the lowest part of the 

Permian. The Montiparus Zone is characterized by the first appearance of the 

keriotheca in the wall microstructure (Zhang, 1984, Figs. 6, 7). 

4. The Carboniferous-Permian boundary should be placed between the Late 

Carboniferous Nephelophyllum-Pseudotimania assemblage Zone and the Early Permian 

Kepingophyllum assemblage Zone, namely between the Shazitang Formation and the 

Longyin Formation of the Longyin section in Guizhou. However, Rui and Zhang 

(1987) noticed that the lowest part ofthe Kepingophyllum assemblage Zone was higher 

than the base of the Pseudoschwagerina Zone. 

5. The lowest part of the Pseudofusulina moelleri Zone and the Protopopanoceras 

Zone in the Longyin section of Guizhou, is correlated with the lowest Sakmarian in 

Russia and it is regarded as the lowest ofthe Permian. According to Ruiand Zhang 

(1987), this consideration of the Carboniferous and Permian boundary is ambiguous, 

because the Pseudofusulina moelleri Zone contains Sphaeroschwagerina and other charac 

teristic elements of the Asselian Stage.


13 

Table 3. 

Different levels proposed to the Carboniferous-Permian boundary in China (after 

Rui and Zhang, 1987). 

Locality Lower Permian Upper Carboniferous 

Nanjing Mis 

Chen, 1934,Sheng.1962 

Chinling Range 

Wang etaL 1973 

Nanjing hits 

Wang,1978 

Puan,Guizhou 

Wuetal., 1979 

Yangel al.,1983 

SouthernJiang 

Yu.1981 

Yangzistratigraphic province 

Rui,1981 

South China 

Sheng., 1982 

Puan,Guizhou 

Zhang, el al, 1982 

Longlin, Guanga 

Long, 1982 

Longlin, Guangxi 

Huang, 1984 

Southern Hunan 

Zhou, 1982 

Nanjing hBis 

Zhang, 1983 

Southwestern Guizhou 

Wuetal., 1983 

Puan,Guizhou 

Zhang, 1983 

Qinling Range 

Ding etal., 1983 

South China 

Wu, etal., 1984 

South China 

Zhang, 1985 

Luodan, Guizhou 

Xiong etal, 1985 

Swine Limestone Member 

Chuanshan Fra 

MdaudaeZ 1 S. tschemyschewi Z PseudoschwaaerinaZ 1 TriMesZ 

YaziFra 

SanBchongFm. 

MiseSlmaZ. PamuinaZ PseudoschwacsrhaZ 1 TriMesZ 

L Permian 

Upper CarbonSerous 

Swine L Mem. 

ChuanshanFm. 

M. daudae Z .Sphaeroschwagerina moelleri Z 1 TriMesZ 

Lower Permian 

Upper CarbonSerous 

ChBisia Fm. LiangshanFra Baomoshan Fra Longyin Fra I Shazitang Fm. 

Robust, 

Sphaeroschwagerina Z 

schellwieniZ Sph. domerosa ISph. constans 

Triticites Z 

Lower Permian" 

UpperCarboniferous 

ChhsiaFm. 

ChuanshanFm. 

Parawenl Z 1Chuanshan. Z 1 

Chftsia Stage 

MapingStage 

Misellina Z PseudoschwaaerinaZ. 1 TriMesZ 

ChBisia Stage 

Maping Stage 

M. daudaeZ 1Schwagerina tschemyschewi Z Pseudosc wagerina Z I Triticites Z 

Lower Permian 

Upper Carboniferous 

Chihsia Stage Longyin Fm Shazitang Fra 

MiseSna daudae Zone Pseudofusulna moelleriZone Ps-ZelliaZ TriMesZ 

ChBisia Fra ChannmoFra Mapina Fm 

Misellina, 

Pseudofusul'ina inusilata- 

Paratusulina Robustoschwagerina Z Pseudoschwagerina Z TriMesZ 

ChihsiaFm. LortfinStaae Maping Stage 

Misellina Z Pamtina- Nagatoella {Daivasies Pseudoschwagerina Z | Triticites Z 

ChBisia F. 

Chuanshan Fm 

M. daudaeZ Staffollal S.cushmaniZ Pseudoschwagerina Z 

ChBisia Fra Swine Limestone Fm. Chuanshan Fra 

M. daudae Z Darvasites oidinatus Z Sphaeroschwagerina moelleri Z Triticites Z 

Proposal 1 Lower Permian U.Carb. 

M daudae 

Bed 

M. 

Rob. 

Psl.- 

Rob. 

Rob. 

schellwieni Q. 

Psl. moelleri- 

Psl. fusiormis 

j 

1 N «£ 

TriMesZ 

Proposal 2 Lower Permian U.Carb. 

Lower Permian 

UpperCarboniferous 

ChBisia Fm. Uanoshan Fm. Baomoshan Fm Longyin Fm. | Shazitang Fm. 

Rob. 

schellwieni Z 

Sphmoschwaaerina Z. 

Sph. domerosa\ Sph. constans 

Lower Permian 

UpperCarbonSerous 

YaziFra

14 

Yasuhiro Ota 

U 

J0.F 

si 

I 

1. Protriticites subschwagerinoides Zone 

2. Triticites montiparus Zone 

3. Triticites schwageriniformis Zone 

4. Triticites dictyophorvs Zone 

5. Triticites shikhanensis compactus Zone 

6. fteudaschwagerina mo/sej - 

Robustoschwagerina xiaodushanica Zone 

7. fteudoschwagerina parabeedei - 

Sphaeroschwagerina sphaerica Zone 

8. fteudoschwagerina robusta - 

Zellia chengkungensis Zone 

9. Pseudofusulina vulgaris - 

laxifusulina iniqua zone 

10. Chalaroschwagerina tumentis Zone 

11. Pamirinachinlingensis Zone 

Fig. 5. Composite stratigraphic section, showing fusulinacean faunas near the Carbonifer 

ous-Permian boundary at Xiaodushan, Guangnan, Easter Yunnan (after Zhou et al., 

1987). 

6. The top of the Baomoshan Formation, namely the Robustoschwagerina Zone is 

correlated with the base of Artinskian Stage and it is regarded as the lowest part of 

the Permian in China. 

In Japan, the definition of the Carboniferous-Permian boundary also has been 

discussed for a long time in several important provinces by many workers. The 

author presents some recent considerations on this problem, by some workers in the 

Akiyoshi Limestone Group. 

Toriyama (1954a, b, 1958) divided the Akiyoshi Limestone Group into the 

following seven fusulinacean zones in descending order. 

Yabeina Zone 

Neoschwagerina Zone 

Parafusulina Zone 

Pseudoschwagerina Zone 

Fusulinella Zone 

Projusulinella Zone 

Millerella Zone 

He subdivided the Pseudoschwagerina Zone into two subzones, the upper, the 

Pseudofusulina vulgaris Subzone and the lower, the Triticites simplex Subzone. Then

South Ural 

Zone 

Paralusulina 

Parafusulina 

soSdissima, 

concessa, 

schellwieni 

Psl. urdalensis 

Psl. callosa, 

Psl. vemeuilis, 

Psl. moelleri 

Sph. 

sphaerica- Psf. 

firma 

Sph 

moelleri- 

Psf. fecunda 

Psf. vulgaris• 

Psf. fusiformis 

D. sokensis 

T. jigulensis 

T. siuckenbergi 

T. acutus • 

T. ardicus 

Montiparus 

montiparus 

£ 

USA 

Texas 

Zone 

Paralusulina 

Pseudo 

schwagerina • 

Monodixodina, 

Pseudo 

schwagerina - 

Triticites, 

Triticites- 

Schwagerina 

Triticites 

ventricosus, 

Triticites 

cullomenensis, 

Triticites 

Irregularis 

O 

South China 

Northeast 

Japan 

Southwest 

RUSSIA 

Darvas of Central Asia Transcaucas 

Zone 

Zone 

Zone 

Stage 

Zone 

Zone 

J 

Misellina 

Nanklnella • Paralusulina 

M. claudiae 

M. bngjinensis - M. prima 

Monodiexodina 

matsubaishi 

Neoschwagerina 

§ simplex- 

Cancellina 

Bolorian 

Misellina 

parvicostata 

M. dyhrenfurthi 

\Chalaroischwagerina 

Kungurian 

Pseudotusutina 

acmeZ. 

Darvasites 

Nagatoella 

Robustoschwagerina schellwieni 

(or StatiellarichZone)- 

Kepingophyllum 

Pseudolusulina 

Misellina 

Pseudoiusulina 

Yakhtashian 

Sakmarian 

Chalaro 

schwagerina 

vulgaris- 

Pamirina 

Robusto 

schwagerina 

schellwieni • 

Parasch mira 

Artinskian 

Sakmarian 

Sphaeroschwagerina 

Monodiexodina 

Sph. sphaerica 

Psl. firma 

£ 

Pseudo 

schwagerina 

Asselian 

Sph.moelleri - 

Psf. fecunda 

Asselian 

Pseudoschwagerina range Zone 

Ps. vulgaris - 

P& fusitormis 

Orenburgian 

D. sokensis 

Orenburgian 

Triticites 

Montiparus range Zone 

Triticites 

Gzhelian 

Kasimovian 

T. jigulensis 

T. siuckenbergi 

T. ecutus - 

T. ardicus 

Montiparus 

montiparus 

Gzhelian 

Kasimovian 

Fig. 6. Assemblage zones of the Permian representative fossils in South 

(after Zhang, 1984). 

China and the international correlation

16 

Yasuhiro Ota 

The first session of 

stratigraphic conference 

China 

The second session of 

stratigraphic conference 

Zhang(1984) 

Central Asia area 

of USSR 

JC c 

Ox 

Palaeofusulina 

s>§ 


.C c 

OR 


Dorashamian 


Codonofusiella 



Dzhulfian 


Yabeina 

Yabeina 

Yabeina 

Midiyan 

Yabeina 




Murgabian 


Cancellina 

Cancellina 

Cancellina 

Kubergandian 

Cancellina 

Bolorian 

Misellina 

Misellina 

Misellina 

Misellina 

o>2> 

Pseudo 

fusulina 

Yakhtashian 

Chalaro 

schwagerina 

Pseudo 

schwager 

ina 

Robusto 

schwager 

ina 

Pseudo 

schwager 

ina 

Robusto 

schwager 

ina 

Sphaero 

schwager 

ina 

Sakmarian 

Robusto 

schwagerina 

Asselian 

"Schwagerina" 

Triticites 

Triticites 

& 

Pseudo 

schwager 

ina 

Orenburgian 

Daixina 

Triticites 

Montiparus 

Gzhelian 

Triticites 

Kasimovian 

T.-Montiparus 

Moscovian 

03 C 

£1 

Fusulina 

Fusulina 

Fusulina 

Fusulina 

Fig. 7. Stratigraphic development of fusuhnaceans (after Zhang, 1984).


17 

AKIYOSHI LIMESTONE GROUP 

Y.OZAWA 

(1923) 

S. HANZAWA 

(1941) 

R. TORIYAMA 

(1953-1957) 

ll 

I 

Sumatrina 

annae 

Yabeina 

Sumatrina 

Neoschwagarina 

Verbeekina 

subzone 

Yabeina 

sniraiwensis 

Neoschwagerina iperina | 

dowillei 

c 

CO 

is 


ambigua 

ParafusuSna 

Verbeekina 

verbeeki 

Neoschwagarina 

craticulifera 

CD 

Q_ 

< 


japonica 

Paralusulina 

lutugini 

Parafusulina 

Paraschwagerina 

Parafusulina 

kaerimizensis 



ojomotosa 



vulgaris 

SI 


muongthensis 

Schwagerina 

Quasffusutina 

Triticites 

Triticites simplex 

c 

2 

"c 

Ctf 

> 

CO 

c 

c 

CD 

Q. 

£ 

Q = 

L 

Fusulinella 

bocki 

Lonsdaleia 

(foriforms 

NagatophyBum 

satoi 

Fusulinella' 

biconica 

Profusulinelta 

beppensis 

MillereOa sp. a 

Fig. 8. The fusulinacean zones of the Akiyoshi Limestone Group (after Toriyama, 1958).


he correlated the base of Pseudoschwagerina Zone (including Triticites simplex Subzone) 

with the base of Sakmarian in Russia, Wolfcampian in North America and 

Sakamotozawan in Japan (Fig. 8). 

Hasegawa (1958, 1963) divided the Akiyoshi limestone Group into eight zones. 

Of them, Profusulinella, Fusulina-Fusulinella and Yabeina-Lepidolina Zones were almost 

the same as those by Toriyama (1954a, b, 1958), but he subdivided Pseudoschwagerina 

Zone into an upper, the Pseudoschwagerina muongthensis Subzone and a lower, the 

Triticites simplex Subzone. At that time, he did not clearly indicate the Carbonifer 

ous-Permian boundary. However, he noticed the Mg-rich and oolitic limestones in 

the lower part of Pseudoschwagerina Zone. 

Murata (1961) divided the Akiyoshi Limestone Group into eight foraminiferal 

zones. He put the Carboniferous-Permian boundary below the base of the Pseudo 

schwagerina Zone, where the subfamily, Schwagerininae first appeared, and the 

genera, Fusulinella, Fusulina and Beedeina disappeared. 

M. Ota (1968, 1977) established 21 fossil zones (Table 4). He considered the 

Carboniferous-Permian boundary below the Triticites simplex Zone. 

Minato, Kato, Nakamura, Niikawa and Hasegawa (1984) gave a review on 

studies of the Carboniferous-Permian boundary in Japan and mentioned that the 

Table 4. Biostratigraphic zones of the Akiyoshi Limestone Group (after M. Ota, 1977). 

Geologic age Name ofthe fossil zone Symbol Thickness 

C 

CO 

E 

Q_ 

Late Lepldollna multiseptata shlraiwensis Zone Puo +25m 

Middle 

Early 

Colania douvillei Zone 

Verbeekina verbeekl Zone 

Neoschwagerina craticullfera Zone 

Afghanellaschenckl Zone 

Parafusulina kaerimlzensis Zone 

Misellina daudiae Zone 

Pseudofusulina ambigua Zone 

Pseudofusulina vulgaris Zone 

Pseudoschwagerina (P.) muongthensis Zone 

Triticites simplex Zone 

PmS 

Pm y 

PmjS 

Pma2 

Pma1 

PIS 

Ply 

PI/5 

Pla2 

Plal 

40m 

20m 

25m 

15m 

25m 

20m 

40m 

50m 

20m 

±50m 

Late Triticites (s. 1.) matsumotoi Zone Cua 20m 

CO 

2 

*^ 

'c 

o 

.a 

I— 

CO 

O 

Middle 

Early 

Beedeina akiyoshiensis Zone 

Fusulinella biconica Zone 

Akiyoshiella ozawalZone 

Profusulinella beppensis Zone 

Pseudostaftella antiqua Zone 

Millerellayowarensts Zone 

Nagatophyllum satol Zone 

Zahrentoldes sp. Zone 

Marginalia toriyama! Zone 

Cmy 

Cm 3 

Cm a 3 

Cm a 2 

Cma1 

CIS 

Cly 

CI0 

CI a 

±30m 

-80m 

20m 

20m 

20m 

60m 

70m 

40m 

80m


relationship between the Lower Permian and Carboniferous deposits in Japan is 

variable from place to place (Fig. 9). 

Ozawa and Kobayashi (1990) reexamined the fusulinacean zones of the 

Akiyoshi Limestone Group, and drew the Carboniferous-Permian boundary between 

the Daixina robusta-"Pseudoschwagerina" minatoi Zone and the "Sphaeroschwagerina" fusiformis 

Zone. Ozawa, Kobayashi and Watanabe (1990) established the new genus 

"Carbonoschwagerina" with Pseudoschwagerina morikawai Igo as the type species. They 

remarked that this genus represents Carboniferous age. They placed the Carbonif 

erous-Permian boundary at the same horizon as Ozawa and Kobayashi (1990). 

Watanabe (1991) emphasized the same opinion that the Carboniferous-Permian 

boundary should be placed under the Sphaeroschwagerina fusiformis Zone. 

Fig. 9. 

Correlation of the Upper Carboniferous and the Lower Permian in Japan (after 

Minato et al., 1984). 

Biostratigraphy of the Akiyoshi Limestone Group near the Carboniferous- 

Permian boundary in the three different areas 

-1-1. Biostratigraphy of the Jigoku-dani area 

The first area investigated, Jigoku-dani, is located in the northwestern of the 

Akiyoshi Plateau(s. s.). This area topographically consists ofa deep valley with NE-


SW trend, ranging from about 200 m to 350 m in altitude and well-developed karst 

topography. M. Ota (1977) confirmed the following fusulinacean zones in this area: 

Fusulinella biconica Zone, Triticites simplex Zone, Pseudofusulina vulgaris Zone and 

Pseudofusulina ambigua Zone. The Akiyoshi Limestone Group in this area is consid 

ered to have originally accumulated in a lagoonal sedimentary environment within 

the Akiyoshi organic reef complex and is geologically inverted in structure. How 

ever, in this area, fusulinacean zones such as the Beedeina akiyoshiensis Zone, Triticites 

(s. 1.) matsumotoi Zone, and Pseudoschwagerina muongthensis Zone of the generalized 

fusulinacean zones of the Akiyoshi Limestone Group (M. Ota, 1977) have not been 

confirmed yet and elements of the fusulinacean fauna have remained unknown. 

Topography of the Jigoku-dani area is characterized by the limestone lapie field 

and it is difficult to confirm the exact localities of the collected materials. Therefore, 

the author selected some traverses to measure with the name ofJI (JI Traverse 1-5) 

and collected materials along the traverses. Materials from localities 300 to 788 are 

mainly discussed here (Fig. 10). 

Limestones in the Jigoku-dani area are generally massive. They are white to 

gray white, but pardy dark brown in color. The dark brown color is considered to 

be caused by the secondary alteration, but the genesis needs to be carefully studied. 

The limestones in this area are ordinarily composed of micrite, with some intercalat 

ing limestone with sparry calcite cements. Frame building organisms of reef en 

vironment are almost absent. These features suggest that the limestones in the 

Jigoku-dani area were mostly accumulated under a low energy lagoon sedimentary 

environment. 

Based on the microscopic study of the collected specimens, 56 fusulinacean spe 

cies including two subspecies among 23 genera are discriminated (Table 5). Dis 

tribution of these fusuhnaceans and distinction of lithofacies are illustrated in Fig. 11. 

Distribution of the characteristic fusuhnaceans and the fusulinacean zones along five 

traverses, JI Traverse 1-5 are shown in Fig. 12. Furthermore, the detailed distribu 

tion of the fusulinacean species and the lithofacies along each traverse are shown in 

Figs. 13 and 14, respectively. 

From these examinations, nine zones including seven subzones were recognized 

in the Jigoku-dani area (Table 6). The representative fusuhnaceans of the proposed 

zones and the thickness of each zone measured along each traverse are shown in 

Table 7. 

From the distribution of these fusulinacean zones, it is confirmed that the 

Akiyoshi Limestone Group in this area has the general strike of N10°W, dipping to 

ward SW with angles of 10 to 20 degrees. Furthermore, the older fusulinacean zones 

are recognizable at higher topographical locations than the younger ones along the 

western slope of the valley, and therefore limestones in this area apparently exhibit an 

inverted succession. In addition, these limestones are mainly composed of micrite 

without the frame builders of organic reefs. They are considered to have accumu-

Fig. 10. The first investigated area, Jigoku-dani, showing survey traverses: JI Traverse 1-5 and their cardinal 

points. 

•3 

a


$ 

- I 

a; 

9! 

3 

3 

SB 

3 

S 

as 

££


8 

sm £33 

isiis 

lis 

me 

Goo

24 

Yasuhiro Ota 

S 

ill] 

8 

as, 

:££ £3333 

CD 

= 

CO 

B 

aSc 

CO 

85 

§3|3^ 

g 

is a 

c


25 

JI Traverse 5 

JI Traverse 3 

1 JI Traverse 1 

JI Traverse 4 

110m 

Fig. 12. Distribution of the characteristic fusulinacean species (shown by the locality numbers) and 

the fusulinacean zones (1-9) along the JI Traverse 1-5. 

The following numbers are used for fusulinacean zones: 1. Fusulinella biconica Zone; 2. Fusulina cf. 

shikokuensis Zone; 3. Obsoletes obsoletus Zone; 4. Montiparus sp. A Zone; 5. Triticites yayamadakensis 

Zone; 6. Schwagerina () cf. satoi Zone; 7. Pseudoschwagerina muongthensis Zone; 8. Pseudofusulina 

vulgaris globosa Zone; 9. Pseudofusulina aff. ambigua Zone. The characteristic fusuhnaceans with 

localities are as follows: 332, Pseudoschwagerina muongthensis (Deprat); 387, Schwagerina () cf. satoi 

(Ozawa); 392, 439, 569, 605, Triticites yayamadakensis Kanmera; 454, 554, Montiparus () sp. A; 

461, Fusulinella biconica (Hayasaka); 465, Fusulinella cf. obesa Sheng; 468, Protriticites toriyamai 

Ota; 477, 633, Obsoletes obsoletus (Schellwien); 489, 538, Protriticites matsumotoi (Kanmera); 517, 

Pseudofiisulinella hidaensis (Kanuma); 520, Protriticites masamichii Ota; 578, Schwagerina sp. A; 663, 

Montiparus sp. A; 686, Triticites yayamadakensis evectus Kanmera; 723, Pseudofusulina () sp. A; 729, 

Pseudoschwagerina sp.; 736, Paraschwagerina sp.; 766, Pseudofusulina aff. ambigua (Deprat).

26 

Yasuhiro Ota 

Fig. 13-1. JI Traverse 1. 

13. Distribution of the characteristic fusulinacean 

species (shown by the locality numbers) and the 

fusulinacean zones (1-9) along the JI Traverse 1-5. 

The following numbers are used for fusulinacean 

zones: 1. Fusulinella biconica Zone; 2. Fusulina cf. 

shikokuensis Zone; 3. Obsoletes obsoletus Zone; 4. Monti 

parus sp. A Zone; 5. Triticites yayamadakensis Zone; 6. 

Schwagerina () cf. satoi Zone; 7. Pseudoschwagerina 

muongthensis Zone; 8. Pseudofusulina vulgaris globosa 

Zone; 9. Pseudofusulina a(T. ambigua Zone.

d5' 

&\p 

•^1 

ftrcniffna cf* ih&oJttieaiit 

Protrtticttts tnxoustotot 

FksoUseiia ef. oka ' 

PtmtiiScixts MiyKBtl I 

Obsofeta obmlems 

J3*3 

NJ 

Tf 

RraAaeBs ttccBir I 

Asulloa cf. ibfibiioeiuff 

Ocaolna obmfcftii 

U) 

AotfiJeftcs aacnmmtDi 

Qiustfuniibakfcs (7) ip.' 

Mostfparm sp. A* 

THttcAmnarioi 

Qiasi&niflaa kmgbshnM 

Qjaiifiaulioj sp. A 

TWtfete»,wyinHicfafcnsft evectus 

TWUcite mJrW 

*T1 

d5' 

S4 

Obsakta obsoSctw \ 

ProtrWctXJ mMBumoal 

ProaiOcttajrtBltklll 

Momtpam (I) sp. A' 

IMtkfttscf.otai 

7Wdc)»»fcJcfawij' 

TWtktet ct bona 

7HUcteiw»m«ftitfmto eveclm 

ScAmijeriai ip. A 

7W(idKirazaJ4( 

7WiJi4ies blcoojrax ' 

TMdcttes •&. dapla 

mtkintytymMctikmilj' 

THtfcftwcf. i»eraii 

QtfHifuja/ins sp. B 

32 

en t3> 

FxudafmuIlBM (J) sp. A 

7Wclcftcs cf. pje»rfrtt/ntplcx 

fteacfafcl»«m«ilia ip.' 

fsnxf«r/n«i(trbia muanftbenllj 

Amscfcw«faiai sp. 

ftrtxfoAuuttu vcfeirti fjcboia' 

fteuctoftnaUai afl. imAtfm 

Acuda/uRtttn cf. vuCjirfs s.«. 

o


.irrestone 

with 

Locally rriaite 

matrix 

Urrestone 

with 

rr.:r;.: 

matrix 

Lines;one 

with 

sparry 

calcrte 

cement 

Blackand 

dark 

brown 

color 

limestone 

Subzone 

Zone 

jrrfistonc 

with 


matrix 

300 

Lirestone 

with 

micritic 

matrix 

Limestone 

with 

sparry 

calate 

cerrent 

BlackanT 

dark 

brown 

color 

limestone 

Subzone 

Zone 

::•:•::•::• 

5-3 

304 

•::•:•:•::•:•: 

306 

V-' 

r/, 

4jl 

ice 

5-2 

"31 

sir 

m 

4« 

316 

317 

319 

7 

i® 

410 

s 

21 :••:•:••: : 

322 

323 

324 

325 

37-i 

41/ 

—28~ 

'•::.•• 

419 

5-1 

3X 

422 

534" 

;.;.... 

311 

313 

318 

436 

360 

•~~ 

440 

y.i 

:•:•:•:•••:•:• 

445 1 

446 

:':•:•: 

4 

361 

~ss~ 

6 

354 

~356— 

—370 

457 

3 

461 

375 

376 

Fig. 14-1. JI Traverse 1. Loc. 388 (upper 

most of the left column) continues to Loc. 

387 (lowermost of the right column). 

375 

"383 - 

-%:•- 

Fig. !•!. Distribution of lithofacies along the JI Traverse 1-5. 

The following numbers arc used for fusulinacean zones: 1. Fusulinella biconica Zone, 2. 

Fusulina cf. shikokuensis Zone: 2-1. Fusulina cf. obesaSubzone, 2-2. Pseudofusulinella hidaensis 

Subzone, 3. Obsoletes obsoletus Zone: 3-1. Protriticites loriyamai Subzone, 3-2. Protriticites 

matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayamadakensis Zone: 5-1. 

Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconkus Subzone, 

6. Schwagerina () cf. satoi Zone, 7. Pseudoschwagerina muongthensis Zone, 8. Pseudofusulina 

vulgaris globosa Zone, 9. Pseudofusulina aff. ambigua Zone.

. . 

. 

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group. Part I 29 

L rrescne 

with 


matrix 

.. rrestc-e 

with 

rrtcritic 

matrix 


with 

sparry 

catate 

cerrent 

Black and 

dark 

brown 

color 

Imestone 

Subzone 

Zone 

Lirrestone 

with 


matrix 


with 

rriaitic 

matrix 

Linesone 

with 

sparry 

calate 

cement 

Backano 

dark 

brown 

color 

Imestone 

Subzone 

Zone 

615 

. 

564 | wmm 

553 

613 

5-3 

561 

560 :- 

"••«.••••— 

,,,,7,7,",',",",., 

559 

4 

607 

555 l 

605 

603 

1 

601 

3-2 

5-2 

5 

:•:•:•: :- 

3 

595 

585 

3-1 

5/9 

578 

5// 

576 • : ::••:•:• 

5/5 • : ::-:-:::-:-: 

57; :•:::. 

5-1 

2-2 

2-1 

2 

570 

559 

Fig. 11-3. JI Traverse 3 (Loc. 569 to Loc. 

616, right column). Loc. 568 (upper 

most of the left column) continues to Loc. 

569 (lowest of the right column). 

1 


568. left column). 


with 

Locality rriaite 

matrrx 


with 

micritic 

matrix 


with 

sparry 

calate 

cerrent 

Backand 

dark 

brawn 

color 

irrestone 

Subzone 

Zone 

Lirrestone 

with 


matrrx 

Lirrestone 

with 

rriaitic 

matrix 

Lirrestone 

with 

sparry 

calate 

cement 

Biackand 

dark 

brown 

color 

rrestrjr.e 

Subzone 

Zone 

•:.-:•:-•.-:•-:•: 

.:•:::•:: 

4/4 

4/3 

4/2 

4/1 

4/0 

3 

483 

3 

2-2 

2 


479, left column). 

i 

459 

iX 

506 

507 

•••: 

• 

2-1 

2 


•180, right column).

— 


jrreacne 

with 


matrix 


with 

micrrtic 

matrix 


with 

sparry 

caldte 

cerrent 

Biackand 

dark 

brown 

color 

limestone 

Subzone 

Zone 

Locality 

« 

Lirrestone 

with 

rriaite 

matrix 

Lirrestone 

with 

micritic 

matiix 


with 

sparry 

calorie 

cerrent 

Bac.K ar,a 

dark 

brown 

color 

limestone 

Subzone 

Zone 

", 

h; 

7a 

705 

704 

9 

5 

771 

698 • •:•••:•-: " 

" W 

•:•:-•:•:•:••:•. 

• 

763 

/60 

685 

684 

•:.-3 

756 

690 

679 

678 

8 

4 

669 

-••:•:• •: • 

 

665 

664 

663 

662 

661 

660 •: ::•:•:• • •:• 

659 

• ••:•.-.. .,• .. 

657 

.••.-•••••••;, 

655 ..:•:•: . 

731 

726 

725 

7 

6 

•:•:•::•.•:•:• 

. • 

615 

648 •:•:••:-:•:••:•:•••:••:• 

32 

3 

5 

.:•••:•.• 

643 

642 

611 

616 

638 

63/ 

/14 

Fig. 14—5. 

788). 

JI Traverse 5 (Loc. 713 to Loc. 

6a 3-1 

:'.' 

631 

630 

659 

(27 

£5 

22 

2 

620 

618 

2-1 

1 

Fig. 11—1. 

712). 

JI Traverse 4 (Loc. 617 to Loc.


Table 6. Fusulinacean zones in ascending order recognized in 

the Jigoku-dani area. 

Fusulinacean zones in the Jigoku-dani area 

9. Pseudofusulina aff. ambigua Zone 

8. Pseudofusulina vulgaris globosa Zone 

7. Pseudoschwagerina muongthensis Zone 

6. Schwagerina () cf. satori Zone 

5. Triticites yayamadakensis Zone 

5-3. Triticites biconicus Subzone 

5-2. Schwagerina sp. A Subzone 

5-1. Triticites saurini Subzone 

4. Montiparus sp. A Zone 

3. Obsoletes obsoletus Zone 

3-2. Protriticites matsumotoi Subzone 

3-1. Protriticites loriyamai Subzone 

2. Fusulina cf. shikokuensis Zone 

2-2. Pseudofusulinella hidaensis Subzone 

2-1. Fusulinella cf. obesa Subzone 

1. Fusulinella biconica Zone 

lated in a relatively low energy lagoon environment within the Akiyoshi organic reef 

complex. Distributions of fusulinacean zones are shown in Fig. 15 and the cross 

sections along A-A', B-B' and C-C, are respectively indicated in Fig. 16. 

The detailed characters of each fusulinacean zone are given as follows. 

1. Fusulinella biconica Zone. 

The Fusulinella biconica Zone is the oldest in the Jigoku-dani area and is exposed 

in the highest part ofthe western slope of this area. The thickness is estimated to be 

about 2 m + . This zone is typified by the occurrence of Fusulinella biconica (Hayasaka). 

Limestones have a general NE strike and dip gently to northwest, but occa 

sionally dip toward the southeast. They are mainly composed of micritic limestones 

with intercalation of limestones with sparry calcite cements. 


The Fusulina cf. shikokuensis Zone conformably overlies the Fusulinella biconica Zone 

and is defined by the occurrence of Fusulina cf. shikokuensis Ishii. This zone is 

subdivided into two subzones, the lower, the Fusulinella cf. obesa Subzone and the 

upper, the Pseudofusulinella hidaensis Subzone. 

2-1. Fusulinella cf. obesa Subzone. 

The Fusulinella cf. obesa Subzone is characterized by the occurrences of Fusulinella 

cf. obesa Sheng in association with Fusulinella cf. shikokuensis Ishii. 

Limestones of this

Table 7. Representative fusuhnaceans in the proposed zones and the thickness of each zone measured along the 

surveyed traverses. 

Representative fusuhnaceans of each zone in the Jigoku-dani area Thickness 

9. Pseudofusulina aff. ambigua Zone (766-788) 

Ji Route 1 Ji Route 3 JI Route 3 Ji Route 4 Ji Route 6 

Pseudofusulina aff. amd&ua[766(16)], Psf. cf. vulgaris b.b.[766(6)]. 42+m, 

83m, 

(736-766) 

17m, 

(729-736) 

11m, 

(723-729) 

8. Pseudofusulina vulgaris globosa Zone 

Pseudofusulina vulgarisglobosa [738d>2, 755(l)-3, 763(2>-3], 

Paraschwagerina spp.[786(2), 756(2), 756(8). 759(1)-1]. 

7. Pseudoschuagerlna muongthensis Zone 

StaffeUamoelleri,Schubertettakingi, SchwagerinaokafuJiiT.S12o.-2], S. primigena[313f\, S. cf. prtncefw[312fj, 

5. sp. A[3S2(2e>7], S. sp. B[S32D2], S. sp. C[311a, 317D],5. sp. D[382b-1], S. (7)aff. Au«fc«ft«wfa[S08c-l), 

PseudoschwagerlnamuongthensisVlSUli-l, 332(la)-3], Ps. sp.[729(1)1. Ps. (7) sp.[800d-b]. 

6. Schwagerina () of. satoi Zone 

Ozawainella off. magna, NankineUa sp. A Sehubertella lata, Triticites hayderuT379d], 7. michiae[379p], 

7. cf. o6ai[S78d-2], 7. cf. pseudosimplex[311 B.-2, 725(1)], 7. aff. stoyrf«:[379c-l], 7. aff. ai»uAii[37Sa-l], 

Schwagerina cf. «to&ais[836a-2,S86e, 336d], S. ()cf. «atoi[387d2], "Pseudofusulina "cf. oacca[336b-3], 

'Psf.' aff. /iwfbnni»[8791-2] Psf. () sp. A[360a, 387c-A 723], Rwosofu3ulinaarclicalS4Ba-l, 354a-2]. 


5-8. Triticites oiconlcus subzone 

Quasifusullna sp. B[890c-1, 614(1)],Triticites biconicw>[392b-l, 392b-2], 7. cf. iso«nji5[608d], 

7. AuroJu>a*/uM392a-2], 7. yayamadakensis [392a-3. S92A-1. 605b-ll. 

5-2. Schwagerina sp. A snbxono 

Triticites biconicus,7. aff. simp/«x(586d], 7. su«u&f[581c-3], 7. yayamadakensislBSl}), 

Schwagerina sp. A[578(6). 586b-2, 586i-l], 5. sp. B. 

5-1. Triticites saurinl subzone 

Triticites cf. oonus[569k], 7. hidensisl421e.-l), 7. mfcAtae[694-(4)], 7. 8auniuT403a-3, 403b, 429a, 429b, 

433a-l], 7. aff. simplex, T. yayamadakensis[489b, 569d], 7. yayamadakensis evectus [694(18), 569'(1), 686(1), 

687(b)-l]. 


Quasifusulinalongissima[675(2), 675(4>2], Quasifusulina sp. A(675(3)], Montiparussp. A[663(l), 676(1), 679(1)], 

M () sp. A[464a. 554(1)]. Triticiteshidensis. 7. cf. otai. 7. saurtro[673(8)l. 

3. ObeoUtee obsoletus Zone 

3-2. Protriticites matsumotoi subzone 

Obsoletes obsoletus[469a7, 637(b)], Protriticites matsumotoli4S9c, 538a, 634(1)], Pwt yano£Wai[540a], 

Quasifusulinoides () sp. [639(1)1. 

3-1. Profrtficltee toriyamal subzone 

Obsoletes obsoletus[4Tla, 532a. 633-1], Protriticites masamichUlBWa), Prot loriyamai [468c]. 

2. Fusulina of. shikokuensis Zone 

2-2. Pseudofusulinella hidaensis subzone 

Pseudofusulinella fcdae/w»[492(2)-2, 517a. 517b], Fusulina ct.shikokuensis[492&-l, 492b]. 

2-1. Fusulinella of. ofreso subzone 

Fusulina ct. shikokuensts[62U2)], 

Fusulinella cf. ©4e*a[465a, 467a]. 


Fusulinella biconica[461a, 618a-l]. 

32+m, 

(332-300) 

76m, 

(387-332) 

15m, 

(392-387) 32+m, 

109m, 

(439-392) 

34m, 

(454-439) 

9m, 

(454-477) 

2m 

(481-477) 

2+m, 

(462-461) 

8m, 

(465-468) 

44+m, 

(489-507) 

(605-616) 

43m, 

(578-605) 

15m, 

(569-578) 

20m, 

(554-569) 

31m, 

(538-554) 

63m, 

(520-538) 

2m, 

(517-520) 

72m, 

(686-723) 

24m, 

(663-686) 

14m, 

(634-663) 

lm, 

(633-634)

Fig. 15. Distribution of fusulinacean zones in theJigoku-dani area. 

The following numbers are used for fusulinacean zones: 1. Fusulinella biconica Zone; 2. Fusulina cf. shikokuensis 

Zone; 3. Obsoletes obsoletus Zone: 1. Montiparus sp. A Zone; 5. Triticites yayamadakensis Zone; 6. Schwagerina () cf. 

Mtoi Zone; 7. Pseudoschwagerina muongthensis Zone; 8. Pseudofusulina vulgaris globosa Zone; 9. Pseudofusulina aff. 

ambigua Zone. 

n

34 

Yasuhiro Ota 

350m 

300m 

250m . 


6. Schwagerina () cf. saroi Zone 


8. Pseudofusulina 

vulgaris globosa Zone 

9. Pseudofusulina 

aff. ambigua Zone 

200m 

A 

1:1 


350m 

300m 


J v' 3. Obsoletes obsoletus Zone 

Montiparus sp. A Zone 

£- S. Triticites yayamadakensis Zone 

250m. 

200m' 

B 

6. Schwagerina () 

t cf. satoi Zone 

7. Pseudoschwagerina 

/ muongthensis Zone 

1:1 a- 

350m 


^ 3. Obsoletes obsoletus Zone 

300m 

.4. Montiparus sp. A Zone 

250m 

^ 


200m 

C 

iiic 

Fig. 16. 

Cross sections along A-A', B-B' and C-C in the Jigoku-dani area.


subzone strike N10°W, gently dipping toward southwest. They are composed of 

micritic constituents, but limestones with sparry calcite cements are intercalated at 

the basal partofthis subzone. Additionally, limestones ofblack to dark brown color 

occur in this basal horizon, though the origin of the black to dark brown limestones 

has not been determined. 

2-2. Pseudofusulinella hidaensis Subzone. 

The base of the Pseudofusulinella hidaensis Subzone is marked by the first occur 

rence of Pseudofusulinella hidaensis (Kanuma) and this diagnostic species is associated 

with Fusulina cf. shikokuensis Ishii. Limestones of this subzone are estimated to be 2 

m in thickness, and have a general NW strike and gentle dip toward the southwest. 

They are characterized by micrite, but are partly intercalated by limestones with the 

sparry calcite cements. 

3. Obsoletes obsoletus Zone. 

The diagnostic species of the Obsoletes obsoletus Zone is Obsoletes obsoletus (Schellwien). 

In theJigoku-dani area, this zone is recognized as an interval from the hori 

zon with the first occurrence of the genus Obsoletes or the genus Protriticites, to the 

horizon with Montiparus () sp. A or Montiparus sp. A. It is subdivided into two subzones, 

the lower, the Protriticites toriyamai Subzone with primitive species of Protriticites, 

and the upper, the Protriticites matsumotoi Subzone characterized by Protriticites matsu 

motoi (Kanmera). 

3-1. Protriticites toriyamai Subzone. 

In this subzone, primitive species of Protriticites, such as Protriticites toriyamai Ota 

and Protriticites masamichii Ota, are associated with the diagnostic species, Obsoletes 

obsoletus (Schellwien). These primitive species of Protriticites are very important to 

determine the upper limit of the Middle Carboniferous. This subzone was named 

after the characteristic occurrences of Protriticites toriyamai Ota. Maximum thickness 

of this zone is estimated as 63 m. Limestones of this zone have a wide variety of 

matrices from micrites to sparry calcites though they are somewhat coarser in grain 

size. Black to dark brown limestones previously mentioned are observed in this 

zone. 

3-2. Protriticites matsumotoi Subzone. 

The Protriticites matsumotoi Subzone is defined by the first occurrence of Protriticites 

matsumotoi (Kanmera). The other constituent species of this subzone are Obsoletes 

obsoletus (Schellwien), Protriticites yanagidai Ota and Quasifusulinoides () sp. This 

zone has an estimated maximum thickness of about 31 m. Limestones of this subzone 

strike NW and have a gentle dip toward the southwest. This zone is mostly 

limestones with micrite matrix, but those with sparry calcite cements are intercalated 

in the lower part of this subzone. The grains of sparry calcite cements are rather 

coarse in size. 

Black to dark brown limestones are common in this zone. 

4. Montiparus sp. A Zone. 

The Montiparus sp. A Zone is characterized by the occurrence of Montiparus sp. A.


However, limestones along some traverses, did not yield Montiparus sp. A, but were 

characterized by Montiparus () sp. A. Montiparus () sp. A is closely similar to 

Montiparus sp. A, except for some features. Limestones of this zone are estimated to 

be about 34 m in maximum thickness. They generally show a NW strike, dipping 

toward southwest direction, with an occasional NE strike, dipping toward northwest 

direction. The main constituent of limestones is micrite. Black to dark brown 

limestones are also present in this zone. The following fusuhnaceans also occur in 

this zone: Quasifusulina longissima (Moller), Quasifusulina sp. A, Triticites hidensis Igo, 

Triticites cf. obai Toriyama, and Triticites saurini Igo. 

5. Triticitesyayamadakensis Zone. 

The Triticites yayamadakensis Zone is defined by the occurrence of Triticites 

yayamadakensis Kanmera. In the Jigoku-dani area, Triticites yayamadakensis Kanmera 

is easily recognized, and is a good index fossil. The estimated thickness of this zone 

is 124m. This zone is subdivided into the following three subzones by characteristic 

fusuhnaceans in ascending order. 

5-1. Triticites saurini Subzone. 

This subzone is characterized by abundance of Triticites saurini Igo. The base of 

this zone is demarcated by the first occurrence of Triticitesyayamadakensis Kanmera or 

Triticites yayamadakensis evectus Kanmera. The following fusuhnaceans are also in 

association with Triticites cf. bonus Chen and Wang, T. hidensis Igo, T. michiae 

Toriyama, T. aff. simplex (Schellwien). 

Triticites yayamadakensis evectus was first described by Kanmera (1958) from the 

Yayamadake Limestone, Kyushu, Japan. He pointed out the difference of the 

stratigraphic horizon between Triticites yayamadakensis yayamadakensis Kanmera and 

Triticitesyayamadakensis evectus Kanmera. However, the difference was not confirmed 

in the Jigoku-dani area. The thickness of this subzone attains 15 m at most. Lime 

stones of this subzone show general strike of about N14°W and dip about 18° toward 

SW. Limestones are mainly composed of micritic matrices, and black to dark brown 

limestones are intercalated in some horizons. 

5-2. Schwagerina sp. A Subzone. 

The Schwagerina sp. A Subzone is characterized by the occurrence of Schwagerina 

sp. A and Triticitesyayamadakensis Kanmera. The lowest boundary of this subzone is 

demarcated by the first occurrence of the genus Schwagerina. The occurrence of 

Schwagerina sp. A was also ascertained from the AK Traverse in front of the Akiyoshidai 

Museum of Natural History and this species possibly has a wide distribution in 

the Akiyoshi Limestone Group. The general strike and dip of limestones in this subzone 

are unknown. However, from the conformable relationship with the underlying 

limestones, they are common to those of the underlying subzone. Furthermore, the 

limestone sequence of this subzone intercalates limestones with sparry calcite cements 

as were seen in the underlying Triticites saurini Subzone. Limestones of this subzone 

yield the following fusuhnaceans such as Triticites biconicus Toriyama, Triticites aff.


simplex (Schellwien), Triticites suzukii (Ozawa), and Schwagerina sp. B. 

5-3. Triticites biconicus Subzone. 

The Triticites biconicus Subzone is characterized by the abundant occurrences of 

Triticitesyayamadakensis Kanmera and the characteristicoccurrence of Triticites biconicus 

Toriyama. Therefore, the fusulinacean constituents of this subzone clearly distin 

guish them from those of other subzones. Triticitesyayamadakensis Kanmera from this 

subzone has a rather advanced form, such as larger shell and thicker spirotheca, than 

those in the lower horizon. Limestones of this subzone have a general strike of about 

N10°W and gently dip to the south ward. The basal part of this subzone mainly 

consists of limestones with sparry calcite cements. Matrices of limestones gradually 

change from sparry calcites to micrites upward in the section. However, the 

uppermost part of this subzone contains coarse grains of fossil fragments of frame 

builders. In the Jigoku-dani area, this zone is the upper limit of distribution of black 

to dark brown limestones. The following fusuhnaceans are recognized in this 

subzone: Quasifusulina sp. B, Triticites cf. isaensis Toriyama and Triticites kuroiwaensis 

Toriyama. 

6-1. Schwagerina () cf. satoi Zone. 

The lowest part of the Schwagerina () cf. satoi Zone is defined by the horizon from 

the first occurrence of Schwagerina () cf. satoi (Ozawa) or Pseudofusulina () sp. A to 

the first occurrence of Pseudoschwagerina muongthensis (Deprat) or Pseudoschwagerina sp. 

The estimated thickness of this zone is 76 m. The following fusuhnaceans are also 

recognized in this zone: Ozawainella aff. magna Sheng, Nankinella sp. A, Schubertella lata 

Lee and Chen, Triticites haydeni (Ozawa), T. michiae Toriyama, T cf. obai Toriyama, 

T. cf. pseudosimplex Chen, T. aff. simplex (Schellwien), T. aff. suzukii (Ozawa), 

Schwagerina cf. stabilis (Rauser), "Pseudofusulina" cf. bacca Morikawa and Isomi, "Psf" 

aff.fusiformis (Schellwien), and Rugosofusulina arctica (Schellwien). 

The fusulinacean index fossil, Schwagerina () cf. satoi (Ozawa) resembles the 

specimen that was first described as Schellwienia satoi by Ozawa (1925). As it has 

been already pointed out by Ozawa (1925) and Toriyama (1958), Schwagerina 

satoi (Ozawa) is intermediate in form between Schwagerina and Pseudoschwagerina. 

Schwagerina () cf. satoi (Ozawa) from the Jigoku-dani area also has an intermediate 

form between Schwagerina and Pseudoschwagerina morikawai Igo and the present form is 

similar to the microspheric form of Pseudoschwagerina. The question whether the 

present species is referable to the inflated schwagerinids is uncertain. This species, 

however, is very important for regional correlation. Fusuhnaceans of this zone are 

distinguished from those of the underlying zone by their rather advanced forms in 

having larger shell, and thicker spirotheca. Weakly developed phrenothecae occur 

in some specimens. The phrenothecae are generally observed in Pseudofusulina, but 

the present specimens are found in a lower horizon than the horizon of Pseudofusulina 

as known before in the Akiyoshi Limestone Group. More detailed studies are 

required to solve the problem of the "Pseudofusulina" Horizon.


Limestones of this zone are mainly composed of micritic matrices. However, 

the upper part of the underlying zone contains some fragments offossils of reef frame 

builders. No evidence of change in lithofacies of the lower Triticites biconicus Subzone 

to the lower part of the Schwagerina () cf. satoi Zone suggest a remarkable hiatus. 

7. Pseudoschwagerina muongthensis Zone. 

The lowest part of the Pseudoschwagerina muongthensis Zone in the Jigoku-dani area 

is marked by the first occurrence of the genus Pseudoschwagerina, namely, Pseudo 

schwagerina muongthensis (Deprat) or Pseudoschwagerina sp. In the Jigoku-dani area, 

well preserved specimens of Pseudoschwagerina were not obtained. Along the AK 

Traverse near the Akiyoshi-dai Museum of Natural History, microspheric forms of 

Pseudoschwagerina are obtained from a stratigraphically slightly lower position com 

pared with that of the megalospheric forms. Along the northern JI Traverse, JI 

Traverse 5, the microspheric form of Pseudoschwagerina also occurs in a lower horizon 

about 2 m below the megalospheric form. However, along the other JI Traverses, 

the microspheric form has not yet been confirmed. Therefore, the boundary on the 

underlying zone is tentatively drawn between the horizons of microspheric form of 

Pseudoschwagerina sp. and megalospheric form of Pseudoschwagerina muongthensis (De 

prat). The estimated maximum thickness of this zone is 32 m-K Limestones in 

the lower part of this zone, consist of rather coarse constituents and intraclasts. The 

upper part of the underlying Schwagerina () cf. satoi Zone is dominated by micritic 

limestones. The changes of lithofacies is present between the upper part of 

Schwagerina () satoi Zone and the lowest part of the Pseudoschwagerina muongthensis 

Zone. However, each zone is conformably distributed with nearly the same strike 

and dip. Therefore, a visible gap is not assumed between the two zones in the field. 

On the other hand, limestones gradually become micritic in texture as the stratigra 

phy is studied from the lower to the upper part in the present zone. This means that 

the energy of the environment decreased. 

The recognized species of this zone are as follows: Staffella moelleri Ozawa, 

Schubertella kingi Dunbar, Schwagerina okafujii Toriyama, Schwagerina primigena Nogami, 

Schwagerina cf. princeps (Ehrenberg), Schwagerina sp. A, Schwagerina sp. B, Schwagerina 

sp. C, Schwagerina sp. D, Schwagerina () aff. kueichihensis (Chen), Pseudofusulina regularis 

(Schellwien) and Pseudoschwagerina () sp. 

8. Pseudofusulina vulgaris globosa Zone. 

The Pseudofusulina vulgaris globosa Zone is characterized by the abundant occur 

rence of Pseudofusulina vulgaris globosa (Schellwien) and the association of Paraschwagerina 

sp. In this zone the author could not directly determine the strike and 

dip of the limestone. The present zone is considered to conformably overlie the 

Pseudoschwagerina muongthensis Zone. Limestones in this zone are estimated to be at 

most 83 m in thickness. They are characterized by micritic texture. However, the 

lowest part of this zone is composed of sparry calcite cements with rather coarse 

grains. The grain size of limestones near the top of the Pseudoschwagerina muongthensis


Zone is micritic. The changes of lithofacies are present between the top of the 

Pseudoschwagerina muongthensis Zone and the lowest part of this zone. 

9-1. Pseudofusulina aff. ambigua Zone. 

The Pseudofusulina aff. ambigua Zone is the youngest zone, characterized by the 

occurrence of Pseudofusulina aff. ambigua (Deprat). The index fossil, Pseudofusulina 

aff. ambigua (Deprat), is closely similar to Fusulina ambigua of Deprat (1913), and 

Pseudofusulina ambigua by Toriyama (1958). However, the present species differs 

from the above species in having a larger proloculus. More specimens are necessary 

to determine the specific position. Distribution of this zone is restricted near the 

bottom ofJigoku-dani along the northern slope. The estimated thickness is 42 m at 

least. This zone is characterized by rather coarse limestones. Near the boundary 

between the underlying zone and the present one, the limestones with sparry calcite 

cements intercalate with somewhat coarse grained varieties. The limestones gradu 

ally decrease in grain size from the lower to the upper, and they become micritic in 

texture. However, they change to limestones with sparry calcite cements near the 

top of this zone. 

-1-2. Correlation 

The Carboniferous and Permian chronostratigraphic units have been examined 

in Japan for a long time and the Middle Carboniferous and Lower Permian 

biostratigraphic units and their boundaries are currently being debated around the 

world. In the Akiyoshi region, the Akiyoshi Limestone Group has been studied 

since Ozawa (1923) and many important studies of Japanese Carboniferous and 

Permian geology were carried out there, for example, the establishment of the 

fusulinacean specific zones of the Akiyoshi Limestone Group (Toriyama, 1958), the 

paleoenvironmental investigation of the Akiyoshi Limestone Group as an organic reef 

complex (M. Ota, 1968), the examination on the geologic history of the lowest to 

lower part of the Akiyoshi Limestone Group in the northeastern part of the Akiyoshi 

Plateau (Yanagida, et al. 1971), and the establishment of the local standard of the 

biostratigraphic units in the Akiyoshi Limestone Group (M. Ota, 1977). Recently, 

the Middle Carboniferous and Lower Permian biostratigraphic units were actively 

discussed and some important results were reported, namely, by Hasegawa (1988), 

Ueno (1989), Ozawa and Kobayashi (1990), Ishii (1990), Watanabe (1991) and Y. 

Ota and M. Ota (1993). The refinement of the fusulinacean zones will contribute 

not only for making clear the stratigraphic transition of fusuhnaceans, but also for 

establishing the phylogeny of fusuhnaceans. In addition, the regional examination 

of the chronostratigraphic units with sedimentological analysis requires careful at 

tention. 

In the investigated area, nine fusulinacean zones including seven subzones were 

discriminated. The older limestones are successively exposed in topographically 

higher positions along the slope ofJigoku-dani without any remarkable hiatus. The

Ishii (1990) 

Rob, schellwieni z. 

Chalaroschwagerina 

vulgaris z. 

'*. muongthensis on£tA< z. 

Sph. fusiformis z. 

T. hidensis z. 

T. exsculptusz. 

T.yayamadakcnsis~ 

iVot 

(Prot) matsumotoi z. 

P. kuriltiensis z. 

,F. ohtanii z. 

B. higoensis z. 

PsfUaT 

FUa. simplicata z. 

Fig. 17. Correlation among the Middle Carboniferous to Early Permian biostratigraphic units established in the 

different areas of the Akiyoshi Limestone Group and relevant sections. 

Watanabe (1991) 

Rob. 

schellwieni schellwieni • 

Psf. vulgaris vulgaris Z. 

Rob. scheUwieni 

pamirica • S. krotowi Z. 

Parasch. 

akiyoshiensis Z. 

5. globulusjaponials 

Ps. miharanoensis Z. 

Alp. saigusai • 

Ps. cf. robusta Z. 

Sph. pavlooi 

Ps muongthensis Z. 

Sph. fusiformis Z. 

"Ps." minatoi Z. 

"Ps * morikawai Z. 

S .msatoiZ. 

M. 

matsumotoi inflatus Z. 

Ob. oo3oieiu«Z. 

Jigoku-dani area 


aff. ambigua Z. 


vulgaris globosa Z. 

AKarea 

Ota and Ota 

Psf. vulgaris Z. 

M. Ota (1977) 

PsTambtgua] 


Hasegawa (1988) 

Psf. vulgaris aubz. 

Ueno (1989) 

Psf. ex. gr. vulgaris z. 

Ozawa and Kobayashi 

(1990) 



muongthensis Z. 

Ps muongthensis Z. 

75 

IPs.) muongthensis Z. 

Pseudoschwagerina Z. 

Alp. () fusiformis z. 

Dutkevttchia 

spUndidaZ 

Ps. n. «p. Z. 

Ps miharanoensis Z. 

Ps. muongthensis Z. 

'Sph." fusiformis Z. 

Schwagerina () 

cf. satoi Z. 

T. simplex Z. 

T. simplex Z. 

T. simplex subz. 

T. simple 

Dx. cf. robusta • 

"Ps" minatoi Z. 

Triticites 

yayamadakensis Z. 

S. tp. A Z. 

TT< 

Yj. " morikawai Z. 

T.(R.)stuckenbergiZ. 

T. (JR.) paraarctieus Z. 

T.exsculptusZ. 

T.yayamadakensis~Z~ 

Montiparus sp. A Z. 

Obsoletes obsoletus Z~. 

Fusulina, 

ef. shikokuensis Z. 

M. sp. A Z. 

Qfdsx,.AZ. 

Prot. matsumotoi Z. 

Psflla. hidaensis Z. 

T. (s. 1.) matsumotoi Z. 

fl. akiyoshiensis Z. 

T. matsumotoi subz. 

'At toriyamai z. 

«!•ot sp. z. 

Beedeina 

akiyoshiensis z. 

M. matsumotoi Z. 

M. montiparus - 

Qfd. ohtanii Z. 

Trot 

subschwagerinoides Z. 

Ob. obsoletus Z. 

P^Ua hidaensis Z. 

fffa. paemtoooefct Z. 

fl. akiyoshiensis Z. * 

Psflla. UoiZ. 

Fusulinella biconica Z. 



FUa. taishakuensis~ 

FUa. biconica z. 

FUa. biconicaZ.


following fusulinacean zones are successively discriminated from the top to the 

bottom along the slope: 1. Fusulinella biconica Zone, 2. Fusulina cf. shikokuensis Zone: 

Fusulinella cf. obesa Subzone, Pseudofusulinella hidaensis Subzone, 3. Obsoletes obsoletus 

Zone: Protriticites toriyamai Subzone, Protriticites matsumotoi Subzone, 4. Montiparus sp. A 

Zone, 5. Triticites yayamadakensis Zone: Triticites saurini Subzone, Schwagerina sp. A 

Subzone, Triticites biconicus Subzone, 6. Schwagerina () cf. satoi Zone, 7. Pseudoschwager 

ina muongthensis Zone, 8. Pseudofusulina vulgaris globosa Zone, and 9. Pseudofusulina aff. 

ambigua Zone. 

In this chapter, the author presents a correlation chart (Fig. 17) of each zone in 

the Jigoku-dani area with Middle Carboniferous to Early Permian biostratigraphic 

units established by workers in different areas of the Akiyoshi Limestone Group. 

1. Fusulinella biconica Zone. 

The Fusulinella biconica Zone was characterized by the occurrence of Fusulinella 

biconica (Hayasaka). This zone was first introduced by Toriyama (1954a) with 

chronostratigraphic position of the Akiyoshian Series for this zone. According to M. 

Ota (1977), the lower part of Fusulinella biconica Zone is characterized by rather 

primitive species of Fusulinella, namely, Fusulinella simplicata Toriyama. Fusulinella 

biconica (Hayasaka) typified the middle part of the zone and Fusulinella itoi Ozawa, 

the upper part. Ueno (1989) divided the Fusulinella Zone into the following two 

zones, the lower, the Fusulinella biconica Zone and the upper, the Fusulinella taishakuensis 

Zone. In Jigoku-dani, the Fusulinella biconica Zone is definitively located at the top of 

the slope of the Jigoku-dani area, but the Fusulinella taishakuensis Zone was not con 

firmed in this area. This zone corresponds to Fusulinella Zone in other areas. 

2. The Fusulina cf. shikokuensis Zone is characterized by the first occurrence of 

subfamily Fusulininae, especially by Fusulina cf. shikokuensis Ishii. 

This zone is divided into two subzones, the lower, the Fusulinella cf. obesa Subzone, 

and the upper, the Pseudofusulina hidaensis Subzone. The Fusulinella cf. obesa 

Subzone, is characterized by Fusulinella cf. obesa Sheng. This subzone probably 

corresponds to the Kurikian Series that was proposed by Kanmera (1952) from the 

fusulinacean biostratigraphy of the Yayamadake Limestone in the outer zone of 

Kyushu. Furthermore, this subzone is stratigraphically correlative with the Beedeina 

akiyoshiensis Zone by M. Ota (1977). According to him, the Beedeina akiyoshiensis 

Zone is typically developed in the Shishide-dai area, the northeastern part of 

Akiyoshi-dai with distinguishable litho- and biofacies from the subjacent zone. In 

Jigoku-dani, limestones of this subzone do not contain reef building organisms and 

are considered to have accumulated in a lagoonal environment within the Akiyoshi 

organic reef complex. Beedeina akiyoshiensis (Toriyama) has not been found yet. 

The difference of the fusulinacean assemblage seems to be dependent on the dif 

ference of the bio- and lithofacies of limestones. 

This subzone is correlated to the 

Fusulina Zone elsewhere. 

The upper subzone, the Pseudofusulinella hidaensis Subzone, is characterized by the


occurrence of Pseudofusulinella hidaensis (Kanuma). This zone was first introduced by 

Ozawa and Kobayashi (1990) in the Akiyoshi Limestone Group. However, at 

present, the occurrence of this species is confined to particular areas. In the Jigokudani 

area, Pseudofusulinella hidaensis (Kanuma) is found in some localities, but its 

distribution could not be traced widely. This subzone is probably correlated with 

the upper part of the upper Fusulina-Fusulinella Zone. 

3. Obsoletes obsoletus Zone 

The Obsoletes obsoletus Zone is defined by the occurrence of Obsoletes obsoletus 

(Schellwien). This zone is subdivided into two subzones, the lower Protriticites 

toriyamai Subzone and the upper Protriticites matsumotoi Subzone. 

The lower, Protriticites toriyamai Subzone comprises primitive species of Protriti 

cites, namely Protriticites toriyamai Ota and Protriticites masamichii Ota. This subzone 

seems to be also characterized by the first appearance of very finely perforated walls 

in genus. Distribution of this subzone is restricted in its stratigraphic distribution. 

The Protriticites toriyamai Subzone is considered to be the basal zone of the Hikawan 

that was first introduced at Hikawa Valley, Kyushu, by Kanmera (1952). Addi 

tionally, this subzone is equivalent to the lower part of Obsoletes-Protriticites Zone or 

Obsoletes Zone in other areas. 

The upper, Protriticites matsumotoi Subzone is characterized by the occurrence of 

Protriticites matsumotoi (Kanmera) with Obsoletes obsoletus (Schellwien). The basal 

boundary of the Protriticites matsumotoi Subzone with the underlying Protriticites tori 

yamai Subzone is marked by the first occurrence of Protriticites matsumotoi (Kanmera). 

Protriticites matsumotoi (Kanmera) was first described by Kanmera (1955) under the 

generic name of Triticites (s. 1.) and this species is a diagnostic one of the Hikawan. 

Here, the author treats this species as the genus Protriticites by its having the 

"Protriticites-tyot wall" only in the outer volution. This subzone may be equivalent 

to a lower part of Hikawan and the upper part of the Obsoletes-Protriticites Zone, and 

can be correlated with the Triticites (s. 1.) matsumotoi Zone by M. Ota (1977). In the 

AK area and some other regions, the occurrence of the genus Quasifusulinoides was 

reported from the upper part ofProtriticites Zone and/or the overlying strata. In the 

Jigoku-dani area, however, the upper part of the present subzone yields Quasifusuli 

noides () sp., but no well-preserved specimen of Quasifusulinoides were obtained. The 

upper part ofthis zone is possibly correlative with the Quasifusulinoides Zone in other 

areas. 

4. Montiparus sp. A Zone. 

The Montiparus sp. A Zone is characterized by the occurrence of the genus 

Montiparus, and the basal boundary of this zone is drawn by the first occurrence of 

Montiparus sp. A or Montiparus () sp. A. The upper limit of this zone is defined by 

the first occurrence of Triticites yayamadakensis Kanmera and T.yayamadakensis evectus 

Kanmera. The genus Montiparus was first introduced by Rozovskaya (1948) as a 

subgenus of Triticites (s. 1.) with the name of Triticites montiparus Ehr. em. Moell.


Davydov (1990) showed the phylogenetic line of Protriticites-Montiparus-Rauserites. In 

the Jigoku-dani area, continuation of the limestone sequence is confirmed without 

any remarkable hiatus from the Protriticites matsumotoi Subzone to the Montiparus sp. A 

Zone. This generic transition from the genus Protriticites to the genus Montiparus in 

the above phylogenetic line is acceptable in the Jigoku-dani area. Therefore it is 

possible to establish the datum level by the first occurrence of the genus Montiparus. 

This zone probably corresponds to the Montiparus Zone or the lower part of Triticites 

(s. 1.) Zone. 

5. Triticitesyayamadakensis Zone. 

The Triticites yayamadakensis Zone is characterized by the occurrence of Triticites 

yayamadakensis Kanmera. This zone is subdivided into three subzones, the lower, the 

Triticites saurian Subzone, the middle, the Schwagerina sp. A, and the upper, the 

Triticites biconicus Subzone. The diagnostic species of this zone, Triticites yayama 

dakensis Kanmera was described from the Yayamadake Limestone (Kanmera, 1955). 

Therefore, the Triticitesyayamadakensis Zone in the Jigoku-dani area is correlated to the 

Triticites yayamadakensis Zone of the upper Hikawan Series (Kanmera, 1952; Tori 

yama 1967). 

The representative species of the lower, the Triticites saurini Subzone, is Triticites 

saurini Igo first reported from Fukuji, Hida Massif, central Japan (Igo, 1957). This 

species has a shell of large size with highly complicated septa and well-developed 

chomata. In the Jigoku-dani area, this species is associated with Triticites yayama 

dakensis evectus Kanmera that was originally reported from a horizon higher than that 

of Triticites yayamadakensis yayamadakensis Kanmera. Therefore, a slight doubt on the 

stratigraphic position of this subzone still remains. More detailed examinations of 

the fusulinacean constituents of this subzone are necessary to confirm the exact 

stratigraphic position. 

The middle part of this zone, the Schwagerina sp. A Subzone, is characterized by 

the abundant occurrence of Schwagerina sp. A. Outside the Jigoku-dani area, this 

subzone is also confirmed along the AK Traverse. The boundary with the lower 

subzone is defined by the first occurrence of the genus Schwagerina. Therefore, the 

basal boundary of this subzone possibly coincides with lower to middle part of the 

Triticites-Schwagerina Zone(s. s.). 

The upper subzone, the Triticites biconicus Subzone, is discriminated by predomi 

nance of Triticites biconicus Toriyama. In theJigoku-dani area, the present subzone 

is distributed over the Schwagerina sp. A Subzone. This subzone also contains Triti 

cites yayamadakensis Kanmera in association with Triticites biconicus Toriyama. Triti 

cites yayamadakensis from this subzone is very similar to Triticites ozawai originally 

described by Toriyama (1958) and Schellwienia montipara (Ehrenberg) by Ozawa 

(1925), respectively from the Akiyoshi Limestone Group. Triticites yayamadakensis 

from this subzone has an intermediate form between the above two species. On the 

other hand, Triticites ozawai Toriyama was reported from the Triticites simplex Zone in


the Akiyoshi Limestone Group (M. Ota, 1977). Summarizing these evidences, the 

Triticites biconicus Subzone possibly corresponds to the upper part of the Triticites 

simplex Zone(M. Ota, 1977). These three subzones, are correlative with the middle 

and upper part of the Triticites simplex Zone (M. Ota, 1977). 

6. Schwagerina () cf. satoi Zone. 

The lower boundary of the Schwagerina () cf. satoi Zone is tentatively drawn by 

the first occurrence of Schwagerina () cf. satoi (Ozawa) and Pseudofusulina () sp. A. 

The distinguishing species, Schwagerina () cf. satoi (Ozawa) from the Jigoku-dani 

area has an intermediate form between the inflated schwagerinids, e.g. Pseudo 

schwagerina, and not inflated ones, and this species is very important for correlation. 

This zone also contains the following fusuhnaceans: Ozawainella aff. magna Sheng, 

Nankinella sp. A, Schubertella lata Lee and Chen, Triticites haydeni (Ozawa), Triticites 

michiae Toriyama, Triticites cf. obai Toriyama, Triticites cf. pseudosimplex Chen, Triticites 

aff. simplex (Schellwien), Triticites aff. suzukii (Ozawa), Schwagerina cf. stabilis 

(Rauser), "Pseudofusulina" cf. bacca Morikawa and Isomi, "Pseudofusulina" aff. fusi 

formis (Schellwien) and Rugosofusulina arctica (Schellwien). In comparison with 

fusuhnaceans of the underlying zone, those of this zone are characterized by having 

advanced forms, such as larger shell and thicker spirotheca. It is apparent that 

fusulinacean diversity rapidly increased in the Schwagerina () cf. satoi Zone. In 

addition, coarse grained limestones with fragments of reef frame builders are inter 

calated near the boundary between the present zone and the underlying zone. The 

changes of lithofacies and faunas are present near the basal boundary of the present 

zone. On the other hand, this zone is also characterized by the appearance of these 

fusuhnaceans that possess the phrenothecae typically recognized in the genus 

Pseudofusulina. Degree of the development is weak, but the phrenothecae can be 

observed in some specimens. Summarizing these facts, the author tentatively 

correlates the basal boundary of the Schwagerina () cf. satoi Zone with the appearance 

of "Pseudofusulina" or the basal boundary of the Daixina Zone. 

7. Pseudoschwagerina muongthensis Zone. 

The Pseudoschwagerina muongthensis Zone is demarcated from the underlying zone 

by the first occurrence of the genus Pseudoschwagerina. This lower boundary possibly 

coincides with the first occurrence of the inflated schwagerinids. However, Schwager 

ina () cf. satoi (Ozawa) in the underlying zone has the intermediate form between 

Schwagerina and Pseudoschwagerina. Therefore, the basal boundary of this zone is 

drawn by using fusuhnaceans with typically inflated shell. In the Jigoku-dani area, 

they are represented by Pseudoschwagerina muongthensis (Deprat) and Pseudoschwagerina 

sp. Unfortunately, well-preserved materials of Pseudoschwagerina have not been 

obtained from the Jigoku-dani area, and as a result the detailed stratigraphic dis 

cussion of this zone is very hard to make clear. However, an obtained sagittal 

section of the microspheric form of Pseudoschwagerina sp. is closely similar to that of 

Pseudoschwagerina morikawai Igo from the AK area in front of the Akiyoshi-dai Muse-


um. Outside the microspheric form of Pseudoschwagerina, the megalospheric form of 

Pseudoschwagerina muongthensis (Deprat) was obtained from a slightly higher horizon 

than that of the former along the JI Traverse 5. This stratigraphic relationship, 

however, was not confirmed in other traverses. This zone can be correlated with the 

strata containing Pseudoschwagerina and typical inflated schwagerinids. Besides, 

limestones near the lowest boundary of this zone are composed of rather coarse 

limestones with sparry calcite cements. Conspicuous changes of lithofacies from the 

top of the Schwagerina () cf. satoi Zone to the basal part of the Pseudoschwagerina 

muongthensis Zone are apparently observed as stated previously. The facies change 

seems to be closely related to the appearance of the genus Pseudoschwagerina. From 

the above facts, the first occurrence of the genus Pseudoschwagerina becomes an 

excellent marker for the correlation of the basal part of the Lower Permian. In 

Japan, the Lower Permian is represented by the Sakamotozawan Series in Sakamotozawa 

and Nagaiwa areas, with the Kitakami massif as the type locality. Toriyama 

(1963) proposed two subzones for the Sakamotozawan, namely the lower Pseudo 

schwagerina morikawai Subzone and the upper Pseudofusulina vulgaris Subzone. Accord 

ing to Kanmera and Mikami (1965a, b), the basal part of the Sakamotozawan Series 

is absent at the type locality. Therefore, the definition of the Sakamotozawan Series 

has become ambiguous. However, the Pseudoschwagerina muongthensis Zone possibly 

corresponds to the lower part of Sakamotozawan Series that was defined as the lower 

Permian by the first occurrence of the genus Pseudoschwagerina. 

8. Pseudofusulina vulgaris globosa Zone. 

The Pseudofusulina vulgaris globosa Zone is characterized by the abundance of 

Pseudofusulina vulgaris globosa (Schellwien). The lower part of this zone in Jigokudani 

area comprises Paraschwagerina spp. Limestones of this zone mostly consist of 

micritic matrices, but those near the base and top of this zone comprise sparry calcite 

cements with coarse grains. Change of lithofacies from the upper part of the under 

lying Pseudoschwagerina muongthensis Zone to the present zone is obvious, but the 

limestone sequence containing Paraschwagerina sp. and Pseudofusulina vulgaris globosa 

(Schellwien) seems to represent a nearly complete succession. The present zone is 

correlated with Pseudofusulina vulgaris Zone in other areas. This zone possibly cor 

responds to the upper or middle part of the Sakamotozawan Series. 

9. Pseudofusulina aff. ambigua Zone. 

The Pseudofusulina aff. ambigua Zone is defined by the first occurrence of 

Pseudofusulina aff. ambigua (Deprat). Distribution of this zone is restricted to the 

bottom of Jigoku-dani, and therefore the detailed characters are not observed. The 

representative species of this zone is Pseudofusulina aff. ambigua (Deprat). This 

species is closely similar to Pseudofusulina ambigua of Deprat (1913), but it differs from 

the latter species in having a slightly larger proloculus and a more developed 

phrenothecae. In the Jigoku-dani area, Pseudofusulina aff. ambigua (Deprat) is 

associated with Pseudofusulina cf. vulgaris s. s. (Schellwien), which is similar to


Pseudofusulina vulgaris of Schellwien (1909) and also resembles Chalaroschwagerina 

infiata of Skinner and Wilde (1965). This zone is tentatively compared with the 

strata containing the genus Chalaroschwagerina, but its precise stratigraphic position is 

unknown. In the Akiyoshi region, Toriyama (1954a, b, 1957, 1958) first divided 

Parafusulina Zone into the lower Pseudofusulina ambigua Subzone and the upper 

Parafusulina kaerimizensis Subzone. The present zone possibly corresponds to the 

previous Pseudofusulina ambigua Zone in the Akiyoshi Limestone Group. 

-1-3. Conclusion 

In the Jigoku-dani area, the Akiyoshi Limestone Group is characterized by the 

following paleontological and lithological compositions and the author's studies led to 

the following conclusions. 

Biostratigraphically, limestones in this area are divided into the nine fusulina 

cean zones including seven subzones, ranging from the Middle Carboniferous to the 

Lower Permian. They are as follows in ascending order: 1. Fusulinella biconica Zone, 

2. Fusulina cf. shikokuensis Zone, 2-1. Fusulinella cf. obesa Subzone, 2-2. Pseudofusu 

linella hidaensis Subzone, 3. Obsoletes obsoletus Zone, 3-1. Protriticites toriyamai Subzone, 

3-2. Protriticites matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayama 

dakensis Zone, 5-1. Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. 

Triticites biconicus Subzone, 6. Schwagerina () cf. satoi Zone, 7. Pseudoschwagerina 

muongthensis Zone, 8. Pseudofusulina vulgaris globosa Zone, 9. Pseudofusulina afT. ambigua 

Zone. 

The above listed zones are easily traceable in this area and indicate that these 

limestones are structurally inverted. 

Lithologically, limestones in this area have micritic matrices without biolithites. 

Sedimentary environment of limestones is considered to be lower energy environ 

ments like a lagoon within the Akiyoshi organic reef complex. Additionally, any 

remarkable stratigraphical gap, such as the lack of an important fossil zone, was not 

confirmed through the fusulinacean zones. This evidence indicates that the lagoonal 

limestones in the area were continuously accumulated through the Middle Carbon 

iferous and Lower Permian. 

In the Jigoku-dani area, Pseudoschwagerina muongthensis Zone is defined by the first 

occurrence of the inflated schwagerinids: pseudoschwagerinids, namely, the genus 

Pseudoschwagerina. The inflated schwagerinids including the genus Pseudoschwagerina 

are supposed to be planktonic during a part of their life cycle (Ross, 1982) and have 

world-wide distribution. Therefore, they are apparently excellent index fossils and 

are the most useful for the correlation of the Lowest Permian. The genus Pseudo 

schwagerina is known from some characteristic lithofacies, such as the biohermal lime 

stones (Ross, 1964). For regional correlation, the associated fossils are indispensable 

for determining the age and paleoenvironment. In this paper, the author prefers to 

correlate the limestones of the Pseudoschwagerina muongthensis Zone to the Lowest

Fusulinacean Biostradgraphy of the Akiyoshi Limestone Group, Part I 47


Permian by taking the first occurrence of the inflated schwagerinids (pseudo 

schwagerinids) into consideration. 

-II-1. The second investigated AK area 

The second investigated AK area is located in front of the Akiyoshi-dai Museum 

of Natural History. The details of the stratigraphy and paleontology in this area 

have already been described by Y. Ota and M. Ota (1993). Here, the author 

reexamines the results of the investigation of the AK area, to compare with those of 

the Jigoku-dani area. 

The selected area represented by AK Traverse is in the normal sequence of the 

Akiyoshi Limestone Group (M. Ota, 1977). This traverse was established along the 

general trend, NE-SW (Fig. 18). The author had thin sections from rock samples of 

56 localities and reexamined the biofacies and lithofacies. 

-II-2. 

Results of the investigations 

-2-(l). Biofacies and Lithofacies 

The limestones are divided into two types by their color in the field. The first 

type is characterized by white limestone whereas the second one is black to dark gray 

color limestone. The former is subdivided into micrite, limestones with the sparry 

calcite cements and intermediate micritic limestone with micrite and sparry calcite 

cements. Dunham's classification (Dunham, 1962) of limestone is used for the 

present study. In the classification he emphasized that the limestone texture is 

important for the analysis of the energy condition. According to his classification, 

limestones along AK Traverse are recognized as the alternation of those of micritic 

matrices and sparry calcite cements. In addition the black to dark brown color 

limestones occur at AK 9, AK 11 and AK 12. 

The distribution ofsedimentary facies 

is shown in Fig. 19. 

Grain components consisting of abundant fusuhnaceans and phylloid algae were 

obtained from many localities in this area, and coarse grained limestones containing 

fragments of crinoids and bryozoans were interbedded in this limestone sequence 

(Fig. 20). 

Summarizing these facts, the sedimentary environment of this area is recon 

structed as the environment near an marginal lagoon within the Akiyoshi organic reef 

complex. 

-2-(2). Analysis of fusulinaceans along AK Traverse 

Almost all localities along AK Traverse yield many fusulinaceans. Lists of the 

identified fusulinaceans on AK Traverse and the composite stratigraphic sections 

with typical fusulinaceans are shown in Table 8 and Figs. 21, 22. On the basis of 

the fusulinaceans along AK Traverse, each horizon of this limestone sequence was 

characterized by the following fusulinacean subfamilies. 

AK 1-AK 6: Fusulinellinae


49 

LEGEND 

Micrite Matrix 

Micritic Matrix 

Sparry Calcite 

Cements 

Black to Dark Brown 

Color Limestone 

Fig. 19. 

Distribution of sedimentary facies along the AK Traverse.


LEGEND 

DEBRIS LIMESTONE 

INCLUDING 

CRINOIDS AND BRYOZOANS 

FUSULINACEAN LIMESTONE 

PHYLLOID ALGAL LIMESTONE 

DASYCLADACEAN ALGAL LIMESTONE 

LIMESTONE CONGLOMERATE 

9 10 20 30 7 

Fig. 20. 

Route map showing therepresentative biofacies and lithofacies of limestones along 

the AK Traverse.


Table 8. 

Distribution of the fusulinacean species in the AK area. 

S^S; 5>PWeS ^Locality t J ^4in!!11 0/o»03 111 45fi 7fi01 H22!22"Z3 3456 790 333 2 4_ 3*44 71 _ 3

. 

Psflls. hidaensis '/.. 

>> 

** 

row 

—i L 

Protriticites matsumotoi/.. Qfd. sp. A Z. Montiparus sp. A Z. 

> > 

CD 

o 

ro co o ^ 

f 

Schwagerina sp. A Z. T. simplex /.. 

>> 

n n c/> •5* 

re •n 

pi 

5 

-1 

5C re 

9 

v: 

o 8 v: 

n 

T. 

U &j 

s 7- 

3 

re 

2 

ps 

X 

0


53 

AK30. 

AK29. 

Pseudofusulina vulgaris 

s. str. (Schellwien) 

I 

AK2a 

Pseudofusulina vulgaris 

globosa (Schellwien) 

Schwagerina stablis (Rauser) 

AK27. 

AK2& 

Pseudoschwagerina PseudoSchwaaerina sp Pseudoschwagerina 

morikawai Igo rseuoosenwagenna sp. muongthensis (Deprat) 

Triticites ellipsoidalis Toriyama 

Rugsochusenella () sp. 

AK23. 

AK22 

,5 

AK21 

AK20 

AK19 

5M 

AKia 

1mm 

Fig. 21-2. 

(Continued).

.-i 

Yasuhiro Ota 

AK34. SSiS 

Pseudofusulina sp. 

AK33 

AK3J 

Sphaeroschwagerina () sp. 

AK31. 

AK3a 

5__3 

Schwagerina 

globulus japonicus Watanabe 

1mm 

5M 

Fig. 21-3. 

(Continued). 

discriminated in ascending order. 

1. Pseudofusulinella hidaensis Zone 

2. Protriticites matsumotoi Zone (s. 1.) 

2-(2). Quasifusulinoides sp. A Zone 

2-(l). Protriticites matsumotoi Zone (s. s.) 


4. Triticites simplex Zone (s. 1.) 

4-(2). Triticites simp/ex Zone (s. s.) 

4-(l). Schwagerina sp. A Zone 


6. Pseudofusulina vulgaris Zone 

The occurrence of these fusulinaceans and the limestone lithology support the 

conclusion that AK Traverse is composed of two nearly complete depositional se 

quences. The first sequence is recognized within AK 1 to AK 35, whereas the 

second sequence is recognized within AK 35 to AK 56. 

The maximum thickness of each zone within the sequences is shown in Table 9. 

Each zone is characterized by the following diagnostic fusulinaceans and stratig 

raphic features (Fig. 23) in ascending order. 


The Pseudofusulinella hidaensis Zone is characterized by the occurrence of Pseudofu-

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part 1 

55 

AK48 

AK47 

Triticites ozawai Toriyama 

Triticites michiae Toriyama 

AK46- 

AK45 

AK44 

AK41. 

AK40. 

AK39 

Quasifusulina sp. 

AK38. 

AK37J 

AK36. 

Montiparus () sp. Protriticites Protriticites 

matsumotoi matsumotoi 

(Kanmera) (Kanmera) 

AK35 

Triticites () all. Obsoletes Obsoletes sp. Montiparus () sp. 

yayamadakensis obsoletus 

evectus Kanmera (Schellwien) 

5M 

1mm 

Fig. 22-1. 

The composite stratigraphic section in the AK area (Second sequence).

56 

Yasuhiro Ota 

AK56. ; 

Schwagerina stabilis (Rauser) 

AK55.; 

x4 

Ozawainella sp. 

Schwagerina cf. compact (White) 

i 

AK54.1 

Schwagerina stabilis (Rauser) 

AK53.3 

Schwagerina () sp. 

AK52j 

AK5tt 

AK50. 2 

AK49.1 

5M 

AK48. i 

x4 N - x4 ^55* x4 

Schubertella kingi Dunbar and Skinner Ozawainella sp. 

1mm 

Fig. 22-2. 

(Continued).

Fusulinacean Biostratigraphyof the Akiyoshi Limestone Group, Part I 57 

Table 9. 

The maximum thickness of each zone in the AK area. 

Fusulinacean zone 

Thickness 

6. Pseudofusulina vulgaris Zone (AK27-29) 13m 

5. Pseudoschwagerina muongthensis Zone (AK25-27) (AK52-56) 11 m 34+ m 


4-(2). Triticites simplex Zone (s. s.) (AK 18-25) (AK46-52) 35 m 42 m 

4-(l). Schwagerina sp. A Zone (AK15-18) (AK41-46) 16m 20 m 

3. Montiparus sp. A Zone (AK9-10, AK12-15) (AK37-41) 14m 12m 


2-(2). Quasifusulinoides sp. A. Zone (AK8-9, AK11) 4 m 

2-(l). Protriticites matsumotoi Zone (s. s.) (AK6-8) 13m 

1. Pseudofusulinella hidaensis Zone (AK1-6) 34+m 

sulinella hidaensis (Kanuma) and the associated Fusulinella sp. 

sists of white micrite limestone. 

This zone mainly con 


The Protriticites matsumotoi Zone (s. 1.) is characterized by the occurrence of 

Protriticites matsumotoi (Kanmera). This zone is subdivided into two zones, namely, 

the lower, the Protriticites matsumotoi Zone (s. s.) characterized by Protriticites matsumotoi 

(Kanmera), and the upper, the Quasifusulinoides sp. A Zone, characterized by 

Quasifusulinoides sp. A. The genus Quasifusulinoides was not confirmed from the 

second sequence in AK Traverse. The Quasifusulinoides Zone reported by Ueno 

(1989) is supposed to be restricted. Therefore, Quasifusulinoides sp. A. Zone is 

tentatively discriminated and it is included in the Protriticites matsumotoi Zone (s. 1.) be 

cause the main fusulinacean constituents of the present two zones belong to Fusu 

linellinae and Fusulininae. 


The Protriticites matsumotoi Zone (s. s.) yields Obsoletes obsoletus (Schellwien), 

Protriticites matsumotoi (Kanmera) and Triticites () aff.yayamadakensis evectus Kanmera. 

Triticites () aff. yayamadakensis evectus Kanmera resembles the Late Carboniferous 

Triticitesyayamadakensis evectus Kanmera from the Yayamadake Limestone, Kumamoto 

Prefecture in general shape. However, the stratigraphic horizon of the present spe 

cies is higher than those of the closely related ones from Jigoku-dani and Yayama 

dake, because the present species is associated with Obsoletes obsoletus (Schellwien). 

The limestones with these species commonly have limestones with micritic ma 

trices. Limestones with sparry calcite cements are distributed near the lower 

boundary of the Protriticites matsumotoi Zone (s. s.). There is a tendency of increased 

micritic matrices toward the upper part of this zone.


Zone 

Pseudofusulina vulgaris Zone 

Pseudoschwagerina muongthensis Zone 

Triticites simplex Zone (s. 1.) 

Triticites simplex Zone (s. s.) 

Schwagerina sp. A Zone 

Species 

Pseudofusulina vulgaris s. s. (Schellwien), 

Pseudofusulina vulgaris globosa (Schellwien), 

Pseudofusulina sp., Sphaeroschwagerina () sp., 

Triticites complicatus Rozovskaya 

Pseudoschwagerina muongthensis (Deprat), 

Pseudoschwagerina morikawai Igo, 

Pseudoschwagerina sp., 

Triticites ellipsoidalis Toriyamai, 

Schwagerina cf. compacts (White), 

Schwagerina stabilis (Rauser), 

AugosochuseneJ/a () sp., 

Schubertella kingi Dunbar and Skinner 

Triticites cf. secalicus (Say), 

Triticites ozawaiToriyama, 

Triticites michiaeToriyama, 

Trinities cf. paraarcticus Rauser, 

Schubertella kingi Dunbar and Skinner, 

OzawaineHa sp. 

Triticites biconicusToriyama, 

Triticites cf. saurini Igo, 

Triticites ozawaiToriyama, 

Triticites exsculptus Igo, 

Triticites sp. B, 

Triticites sp.C, 

Schwagerina sp. A, 

Quasifusulina sp. A, Quasifusulina sp., 


Montiparus sp. A Zone Triticites sp. A, 

Triticites () sp., 

Sciitvageriiiaf) sp. A, 

Montiparus sp. A, 

Montiparus () sp. A, 

Protriticites matsumotoi (Kanmera) 

fro(ritrcires matsumoroi Zone (s. 1.) 

Quasifusulinoides sp. A Zone 

Protriticites matsumotoi Zone(s. s.) 

Pseudofusulinella hidaensis Zone 

Quasifusulinoides sp. A 

Quasifusulinoides sp. 

Triticites () aff. yayamadakensis evectus Kanmera, 

ft-otrific/res matsumotoi (Kanmera), 

Ohso/eres obsoletus (Schellwien) 

Pseudofusulinella hidaensis (Kanuma) 

Fig. 23. 

Fusulinacean zones and the faunal elements of each zone in the AK area. 


The Quasifusulinoides sp. A Zone is discriminated by the first occurrence of 

Quasifusulinoides sp. A. This zone is only confirmed in the first sequence in AK Tra 

verse with a maximum thickness of about 4 m. 


The diagnostic species of this zone is Montiparus sp. A, and the associated fossils 

are as follows: Protriticites matsumotoi (Kanmera), Montiparus () sp. A, Schwagerina () 

sp. A, Triticites sp. A, and Triticites () sp. In this zone limestones with sparry calcite 

cements gradually change to micritic in the upper part of the section. Protriticites 

matsumotoi (Kanmera) was found in limestones with sparry calcite cements in the 

lower part of the present zone. The occurrence of Protriticites matsumotoi (Kanmera) 

which is the diagnostic species of the underlying zone probably reveals that 

Protriticites matsumotoi (Kanmera) and other associated species are derived from the


underlying limestones. 


The Triticites simplex Zone (s. 1.) is characterized by the occurrence of Triticites 

and Schwagerina, comparing with the Triticites-Schwagerina Zone (s. s.). 


The Schwagerina sp. A Zone is characterized by the predominance of Schwagerina 

sp. A. The lower boundary of this zone in the first sequence in AK Traverse is 

drawn at the horizon characterized by the occurrence of Triticites exsculptus Igo, 

Triticites ozawai Toriyama and Triticites cf. saurini Igo, whereas that of this zone in the 

second sequence is tentatively drawn at the horizon where Quasifusulina sp. occurs 

and lithofacies change from limestones with micrite matrices to those with sparry 

calcite cements. 

Schwagerina sp. A is similar to Rugosofusulina sp. A reported by Hasegawa (1988). 

However, the former is distinguished from the latter by its very weak rugosity of wall. 

The specific constituents of this zone are as follows: Ozawainella sp., Quasifusulina sp. 

A, Quasifusulina sp., Triticites biconicus Toriyama, Triticites exsculptus Igo, Triticites 

ozawaiToriyama, Triticites cf. saurini Igo, Triticites sp. B and Triticites sp. C. 

The lower part of the present zone is predominant in limestones with sparry 

calcite cements and these contain Schwagerina sp. A. Limestones with micrite matrices 

increase toward the upper part of this zone. 

4-(2). Triticites simplex Zone (s. s.) 

In the AK area, Triticites simplex (Schellwien) was not confirmed. However, 

the specific assemblages of fusulinaceans identify them as members of Triticites simplex 

Zone (s. s.), which is equivalent to the upper part of the Triticites simplex Zone (s. 1.) 

(M. Ota, 1977). The following fusulinaceans are common in this zone: Ozawainella 

sp., Schubertella kingi Dunbar and Skinner, Schubertella sp., Schwagerina sp., Triticites 

michiae Toriyama, Triticites ozawai Toriyama, Triticites cf. secalicus (Say) and Triticites 

cf. paraarcticus Rauser. This zone mainly consists of limestones with micritic matri 

ces. Limestones with sparry calcite cements appear and are interbedded with the 

micritic ones in the upper part of this zone. The energy condition of the depositional 

environment is considered to have shifted from lower to higher. 


The Pseudoschwagerina muongthensis Zone is characterized by the occurrence of 

Pseudoschwagerina muongthensis (Deprat) and the lower boundary of this zone is defined 

by the first appearance of Pseudoschwagerina (Pseudoschwagerina morikawai Igo). Along 

the first sequence of AK Traverse, Pseudoschwagerina morikawai Igo, the microspheric 

form first occurs at a horizon about 8 m lower than that of Pseudoschwagerina muongth 

ensis (Deprat), the megalospheric form. However, Pseudoschwagerina muongthensis 

(Deprat) is associated with Pseudoschwagerina morikawai Igo at AK 26. Furthermore, 

the boundary of the Pseudoschwagerina muongthensis Zone with the underlying zone was 

formerly drawn by the first occurrences of Pseudoschwagerina [Pseudoschwagerina


muongthensis (Deprat)], including megalospheric and microspheric forms. There 

fore, the base of the present Pseudoschwagerina muongthensis Zone is demarcated by the 

first occurrence of the inflated schwagerinid, Pseudoschwagerina. Along the second 

sequence, Pseudoschwagerina was not found, but the zone was recognized from a hori 

zon (AK 52), where advanced fusulinaceans occurred. 

Limestones of the first sequence yield the following fusulinaceans: Pseudo 

schwagerina muongthensis (Deprat), Pseudoschwagerina morikawai Igo, Pseudoschwagerina 

Fig. 24. Distribution of fusulinacean zones in the AK area (modified from Hasegawa, 

1992).


sp., Rugosochusenella () sp., Triticites ellipsoidalis Toriyama and Schwagerina stabilis 

(Rauser). The second sequence yields Schwagerina stabilis (Rauser), Schwagerina cf. 

compacta (White), Schwagerina () sp., Schubertella kingi Dunbar and Skinner, and 


This zone is, as a whole, composed of micritic limestones except for the upper 

part. Limestones across the boundary between the present zone and the underlying 

zone along the first sequence change upward from those with sparry calcite cements 

to micritic. Limestones along the second sequence, however, are mainly composed 

of micritic limestones on both sides of the boundary. Limestones with sparry calcite 

cements are common in the upper part of the present zone. They suggest a relative 

ly high energy environment and yield abundant Schwagerina, such as Schwagerina 

stabilis (Rauser). The lack of limestones with sparry calcite cements near the lower 

boundary of the Pseudoschwagerina muongthensis Zone in the second sequence, probably 

suggest that these micritic limestones were accumulated in an environment in which 

the inflated schwagerinids, i.e. Pseudoschwagerina, could not exist. 


The Pseudofusulina vulgaris Zone in the AK area is characterized by the diagnostic 

species, Pseudofusulina vulgaris (Schellwien), and the following associated species, 

Triticites complicatus Rozovskaya, Sphaeroschwagerina () sp., Pseudofusulina vulgaris 

globosa (Schellwien) and Pseudofusulina sp. This zone is characterized by limestones 

with the micritic matrices. 

From distribution of the zones (Fig. 24), it has become clear that the succession 

of AK Traverse consists of two nearly complete limestone sequences, possibly 

separated by the NE- SW fault (shown by Ozawa and Kobayashi, 1990). 

-II-3. 

Correlation 

-3-(l). Correlation (Within Japan) 

In this chapter the author presents the tentative correlation of fusulinacean zones 

of the Akiyoshi Limestone Group of the AK area and a reference proposal for the 

subdivision of the Middle Carboniferous and Lower Permian fusulinacean zones 

(shown in Fig. 17). 


The characteristic species of this zone is Pseudofusulinella hidaensis (Kanuma), 

originally described by Kanuma (1953) as Wedekindellina () hidaensis. Ozawa and 

Kobayashi (1990) first treated this species under the generic name of Pseudofusulinella 

and established the Pseudofusulinella hidaensis Zone with the diagnostic species. The 

phylogenetic trend of Pseudofusulinella was studied by Ozawa (1967) and Wilde 

(1971). According to Kanuma (1953), this species has a small elongate fusiform 

shell with a straight axis of coiling, inflated central area, bluntly pointed poles and 

slightly concave lateral slopes. In addition chomata are large and massive, and 

axial fillings are well developed. Wedekindellina Dunbar and Henbest, 1933 is char-


acterized by its elongated small shell, and well developed axial fillings and four lay 

ered wall with perforations. To the contrary, Pseudofusulinella Thompson, 1951 has a 

spirotheca composed of a tectum and diaphanotheca with very minute but distinct 

pores. The massive chomata in the center of the shell cover the lower surfaces of 

spirotheca to give it the appearance of spirotheca of four layers as found in Fusulinella 

and Fusulina. Pseudofusulinella is distinguished from Fusulinella by its younger occur 

rences than the latter and by having different features of the wall and axial fillings. 

From its general shapes and features, the obtained specimen should be referable to 

Pseudofusulinella hidaensis (Kanuma). The Pseudofusulinella hidaensis Zone of the author 

is correlated with the same zone by Ozawa and Kobayashi (1990). In this inves 

tigated AK Traverse, Beedeina akiyoshiensis (Toriyama) which is the diagnostic species 

of the Beedeina akiyoshiensis Zone (M. Ota, 1977) was not confirmed. Hence it is 

very difficult to directly correlate the Pseudofusulinella hidaensis Zone with the Beedeina 

akiyoshiensis Zone. Nevertheless the present zone corresponds to the Beedeina 

akiyoshiensis Zone based on biostratigraphic relationship between the present zone and 

the underlying and overlying zones. Ueno (1989) recognized the Beedeina akiyoshi 

ensis Zone between the upper, Fusulinella taishakuensis Zone and the lower, Protriticites 

sp. Zone. According to him, only Pseudofusulinella sp. (sp. nov.) was reported from 

Protriticites sp. Zone. Ueno (1991b) reported that Pseudofusulinella (Kanmeraia) 

praeantiqua Nassichuk and Wilde was found in the uppermost part of the Protriticites 

sp. Zone and the lower part of the Quasifusulinoides toriyamai Zone (Ueno, 1989), but 

the detailed relationships between the Pseudofusulinella hidaensis Zone and these zones 

are not clear. However, Fusulinella biconica Zone is correlative with the Fusulinella 

biconica Zone of Hasegawa (1988) and Ozawa and Kobayashi (1990). On the 

other hand, the Fusulinella taishakuensis Zone was first introduced by Okimura (1987) 

and is characterized by the occurrence of Fusulinella taishakuensis established by Sada 

and Yokoyama (1970). The Fusulinella taishakuensis Zone is associated with the 

following fusulinaceans: Fusulinella biconica (Hayasaka), Fusulinella simplicata Tori 

yama, Fusulinella bocki Moller and Fusulinella subsphaerica Toriyama. Judging from 

the constituents of the preceding zones, the Fusulinella taishakuensis Zone and the 

Fusulinella biconica Zone (Ueno, 1989) correspond to the Fusulinella biconica Zone (M. 

Ota, 1977). 



Protriticites matsumotoi (Kanmera) is the diagnostic species of this zone. This 

species was described by Kanmera (1955) as a representative species of Hikawan 

Series and is known as a primitive species of this genus. In well preserved speci 

mens of Protriticites matsumotoi (Kanmera), the spirotheca of the third to the fourth 

and occasionally the fifth volutions appear to be composed of four layers. The 

spirothecal characters closely resemble those of Fusulinella Moller. In mature 

specimens, the spirotheca of the fifth to mature volutions have a clearly discernible


keriotheca. The classification of Triticites (s. 1.) and its evolution have been discussed 

since Rozovskaya (1948) classified Triticites (s. 1.) into four subgenera, Triticites (s. 

s.), Montiparus, Rauserites and Jigulites. Some considerations concerned with their 

several variations are present. One variation is the "Protriticites-type wall". Rauser 

and Fursenko (1959) described the wall structure of Protriticites that it is perforated 

and composed of four-layers in the inner volutions and three-layers in outer ones, 

namely a tectum, protheca and outer tectorium. The same structure of Protriticites 

was also noticed by Loeblich and Tappan (1988). Sheng, Zhang and Wang 

(1988) also confirmed that the inner spirotheca of Protriticites were composed of four 

layers like Fusulinella, but the outer spirotheca were composed of a tectum and the 

inner and outer tectoria. They also mentioned that Protriticites was an intermediate 

form between Fusulinella and Triticites (s. s.). Rozovskaya (1950) clearly illustrated 

the keriothecal wall in Protriticites. Putrya (1948) remarked on the complicated wall 

of Protriticites in his original description of the genus. He noticed that it is composed 

of a tectum, diaphanotheca and two tectoria. Furthermore, he noticed that the 

diaphanotheca, tectoria and chomata possess the structure of fine alveoli, and the 

coarser ones are recognizable in the inner tectorium. In the outermost whorl the 

alveolers structure reaches diaphanotheca. Davydov (1990) proposed the lineage 

from Protriticites to Rauserites, through Montiparus. According to him, the inner 

tectorium which is considered as a characteristic feature of Montiparus is only present 

in the inner whorls where the keriothecal wall is not present. Summarizing 

preceding evidence, it is noticed that Protriticites has the inner tectorium in the outer 

volution and if we recognize the inner tectorium in outer volution of a specimen, then 

it might belong to Protriticites. Triticites (s. 1.) matsumotoi by Kanmera (1955) has a 

Protriticites-type wall only in the outer volutions. Based on these facts, the author 

treats this species under Protriticites. Hasegawa (1988) treated this species as the 

diagnostic species of the Triticites matsumotoi Subzone. According to hisopinions, this 

species has very primitive features of Triticites (s. 1.). Additionally, the fauna of the 

Triticites (s. 1.) matsumotoi Zone is missing in some areas. The fauna of the Triticites 

simplex Zone directly overlies the Fusulinella-Fusulina Zone in some cases. Therefore, 

he interpreted that Protriticites was able to migrate to the place where a fusulinacean 

favorable environment appeared in the early stage. Recently, a primitive-Triticites 

(s. 1.) fauna, including Protriticites, was reported from the Akiyoshi region and some 

other districts. Hence, the author correlated the Protriticites matsumotoi Zone (s. s.) 

with limestones, bearing species of primitive Triticites (s. 1.). 

The present Protriticites matsumotoi Zone (s. s.) corresponds to the Triticites (s. 1.) 

matsumotoi Zone (M. Ota, 1977), the Triticites matsumotoi Zone (Hasegawa, 1988) and 

the Protriticites sp. Zone (Ueno, 1989). Furthermore it is correlative with the 

Obsoletes obsoletus Zone (Watanabe, 1991) and the Protriticites (P.) matsumotoi Zone 

(Ishii, 1990).



The Quasifusulinoides sp. A Zone is characterized by the occurrence of Quasifusuli 

noides. The occurrence of this zone is restricted and thus it is included in the 

Protriticites matsumotoi Zone (s. 1.) on the basis of its confined distribution and the 

stratigraphic relationship between the overlying and underlying zones. Ueno (1989) 

established the Quasifusulinoides toriyamai Zone and this zone is correlated with the 

Quasifusulinoides sp. A Zone. The present zone may be also equivalent to the lower 

part of the Montiparus montiparus-Quasifusulinoides ohtanii Zone (Ozawa and Kobayashi, 

1990) and the upper part of the Obsoletes obsoletus Zone (Watanabe, 1991). In the 

Jigoku-dani area, well-preserved Quasifusulinoides do not occur, but Quasifusulinoides () 

sp. was obtained from the Protriticites matsumotoi Subzone. Therefore, the present 

Quasifusulinoides sp. A Zone probably corresponds to the Protriticites matsumotoi Subzone 

of the Jigoku-dani area. 


This datum level is defined by the occurrence of Montiparus. As mentioned 

before, Montiparus was first introduced as a subgenus in four subgenera of Triticites (s. 

1.) with Triticites montiparus Ehr. em. Moell. as the type species by Rozovskaya 

(1948). However, the variations and definitions of Montiparus are ambiguous, and 

some disagreements about the genus are present. Wilde (1984) treated Montiparus 

Rozovskaya, 1948 as a synonym of Schwagerina montipara (Ehrenberg, 1854) emend. 

Dunbar and Skinner, 1936, and proposed the new name of Eotriticites. In short, 

Montiparus has historically two different types and thus the definition of Montiparus is 

unclear. The obtained specimens should be referred to Montiparus Rozovskaya, 

1948 with the following type species, Triticites (Montiparus) montiparus Rozovskaya, 

1948=Fusulina montipara Ehrenberg emend. Moller, 1878. Montiparus sp. A is a 

diagnostic species of the Montiparus sp. A Zone. 

The Montiparus sp. A Zone is also associated with Protriticites matsumotoi (Kan 

mera), Montiparus () sp. A, Schwagerina () sp. A, Triticites sp. A and Triticites () sp. 

This zone is correlated with the lower part of the Triticites simplex Zone (M. Ota, 

1977), because Triticites in the present zone has a relatively primitive form. More 

over, this zone probably corresponds to the upper Montiparus montiparus-Quasifusuli 

noides ohtanii Zone and the Montiparus matsumotoi Zone (Ozawa and Kobayashi, 1990), 

the Triticites yayamadakensis Zone (Ishii, 1990) and the lower part of the Triticites 

simplex Zone (Hasegawa, 1988). 



The Schwagerina sp. A Zone is distinguished by the characteristic occurrence of 

Schwagerina sp. A. This zone is associated with occurrences of the following species: 

Triticites biconicus Toriyama, Triticites exsculptus Igo, Triticites ozawai Toriyama, 

Triticites cf. saurini Igo, Triticites sp. B, Triticites sp. C, Quasifusulina sp. A, Quasifusulina 

sp. and Ozawainella sp. Zhang (1991) placed the Triticites-Schwagerina Zone under


Pseudoschwagerina Zone and reported the first occurrence of Schwagerina in the lower 

part of the Triticites siuckenbergi Zone. Kanmera, Ishii and Toriyama (1976) also 

established the Schwagerina Zone under the Pseudoschwagerina Zone. The present 

Schwagerina sp. A Zone corresponds to Triticites-Schwagerina Zone (s. s.) and is tenta 

tively correlated with the lower parts of the Triticites simplex Zone (M. Ota, 1977) and 

the Triticites yayamadakensis Zone in the Jigoku-dani area. 


The specific constituents of the Triticites simplex Zone (s. s.) are as follows: 

Ozawainella sp., Schubertella kingi Dunbar and Skinner, Schubertella sp., Schwagerina sp., 

Triticites michiae Toriyama, Triticites ozawai Toriyama, Triticites cf. paraarcticus Rauser 

and Triticites cf. secalicus (Say). Unfortunately, Triticites simplex (Schellwien) was 

not collected in this investigation. However, judging from the coexisted fusulina 

ceans, the specific assemblage corresponds to that of the upper part of Triticites simplex 

Zone (M. Ota, 1977). It is also similar to those from the upper part of the Triticites 

yayamadakensis Zone to Schwagerina () cf. satoi Zone of the Jigoku-dani area. In 

addition, the Triticites simplex Zone (s. s.) is correlated with the upper part of the 

Triticites hidensis Zone (Ishii, 1990), the Triticites (Rauserites) paraarcticus and Triticites 

(Rauserites) siuckenbergi Zones (Ozawa and Kobayashi, 1990), the upper part of the 

Triticites simplex Zone (Hasegawa, 1988) and the upper Triticites "simplex" Zone 

(Ueno, 1989). 


The Pseudoschwagerina Zone was formerly divided into two subzones by Toriyama 

(1954a), namely the lower Triticites simplex Subzone and the upper Pseudofusulina 

vulgaris Subzone (Toriyama, 1954a). Hasegawa (1963) subdivided the Pseudo 

schwagerina Zone into two subzones, the lower, the Triticites simplex Subzone and the 

upper, the Pseudoschwagerina muongthensis Subzone. The Pseudoschwagerina muongthensis 

Subzone was treated as the Pseudoschwagerina (P.) muongthensis Zone, and the Triticites 

simplex Subzone as the Triticites simplex Zone by M. Ota (1977). The datum level of 

this zone is formerly demarcated by the first occurrence of inflated schwagerinids, i.e. 

Pseudoschwagerina muongthensis (Deprat), including megalospheric and microspheric 

forms. Therefore, the lowest part of the present zone in the AK area coincides with 

the occurrence of Pseudoschwagerina morikawai Igo. Many fusulinacean workers have 

studied before on the inflated schwagerinids and their paleoecology and paleobiogeography. 

Studies on their provinciality were also presented by Ross (1962, 

1963a, 1964, 1967, 1982) and Gobbett (1973). Ross (1982) mentioned that several 

genera among the schwagerinids were probably planktonic during a part of their life 

cycles. Ross (1962, 1963a, 1964, 1967) examined their evolution, migrations and 

dispersal in detail. Ross (1967, 1973) pointed out the difference of each province 

based on the paleobiogeographic separation of fusulinid faunas and also discussed the 

lineage of Protriticites. A lineage with Montiparus-Obsoletes-Triticites was confirmed 

only in the Eurasian- Arctic province. Whereas only Triticites was recognized at the


same stratigraphic positions in Mid-continent province. Ross (1962, 1963a, 1964) 

classified the pseudoschwagerinids into eight complexes and he discussed their 

details. From these studies, he concluded that the greatest diversity of them took 

place in the Tethyan seaway in later Wolfcampian time. On the other hand, 

Gobbett (1973) discussed Pseudoschwagerina as a cosmopolitan genus. As mentioned 

above, it is very effective to use the datum level defined by the first occurrence of the 

inflated schwagerinids for accurate global correlation. Rui and Zhang (1987) also 

noticed that pseudoschwagerinids might be used for global correlation, owing to their 

rapid evolution and global distribution. The correlation of the Pseudoschwagerina 

Zone has been discussed by many authors, such as Hanzawa (1942), Hayasaka and 

Minato (1954), Fujimoto (1959), Fomichev (1960), Kahler (1961), Rauser (1965) 

and Lapkin and Kats (1990). Although the inflated schwagerinids show global 

distribution, their occurrence seems to be restricted to somewhat coarser sediments. 

Evidences for this was given by Ross (1964). Therefore, examination of their 

accompanying fossils is indispensable for accurate correlation. The present zone is 

correlated with the Pseudoschwagerina (P.) muongthensis Zone (M. Ota, 1977), and the 

Pseudoschwagerina muongthensis Zone in the Jigoku-dani area. The lower boundary of 

this zone approximately coincides with those of the Sphaeroschwagerina fusiformis Zone 

(Ishii, 1990, Watanabe, 1991), the "Sphaeroschwagerina" fusiformis Zone (Ozawa and 

Kobayashi, 1990) and the Alpinoschwagerina ()fusiformis Zone (Ueno, 1989). 


The base of this zone is marked by the occurrence of the diagnostic species, 

Pseudofusulina ex. gr. vulgaris (Schellwien). Several studies of the systematics of 

Pseudofusulina have been carried out internationally. Davydov (1988a, b) examined 

in detail the origin and development of the pseudofusulinids. However, discussions 

on the systematics, classification and stratigraphic significance of the pseudofusu 

linids still continue. Zhang (1983, 1991) discriminated "Pseudofusulina Bed" under 

the Pseudoschwagerina Zone, and correlated this bed with lower Daixina sokensis Zone. 

According to him, Pseudofusulina stratigraphically occurs in a bed lower than that 

bearing Pseudoschwagerina. Rauser (1951) recognized the Pseudofusulina Horizon 

beneath the Schwagerina Horizon in association with primitive species of Triticites. In 

the "Pseudofusulina Horizon", the earliest pseudofusulinids, i.e. Pseudofusulina krotowi 

(Schellwien) and Pseudofusulina paragregaria Rauser occur. Naoumova and Rauser 

(1964) reported the occurrence of two different types of these Pseudofusulina from 

different stratigraphic horizons. Because of different reports, the correlation of the 

Pseudofusulina Zone is very difficult. An urgent task is the clarification of the origin 

and phylogeny of Pseudofusulina. 

The present Pseudofusulina vulgaris Zone corresponds to the Pseudofusulina vulgaris 

Zone (M. Ota, 1977), the Pseudofusulina vulgaris Subzone (Hasegawa, 1988), the 

Pseudofusulina ex. gr. vulgaris Zone (Ueno, 1989), the Chalaroschwagerina vulgaris Zone 

(Ishii, 1990), the Paraschwagerina akiyoshiensis-Pseudofusulina firm Zone, the Robusto-


schwagerina schellwieni pamirica-Schwagerina krotowi Zone and the Robustoschwagerina 

schellwieni schellwieni-Pseudofusulina vulgaris vulgaris Zone (Watanabe, 1991), and the 

Dutkevitchia splendida Zone and Pseudofusulina vulgaris Zone (Ozawa and Kobayashi, 

1990). 

-3-(2). Correlation (International) 

In this chapter, tentative correlation between the investigated AK area and the 

reference sections is examined. The name of the Carboniferous is derived from 

England, and the name of Permian from "Perm" to the west of the Ural Mountains. 

The Carboniferous and Permian Systems were established in different areas with 

different facies. There is so far no consensus of the definition of the boundary 

between the two systems. Therefore, each worker has applied his own definition to 

each stratigraphical division. Even in the stratotype, several proposals for its 

division are present. Because of this situation, the refinement of biostratigraphic 

units and accurate international correlation of the Upper Carboniferous and Lower 

Permian seems to be difficult and chaotic. 

The following zones along AK Traverse are tentatively correlated with the 

biostratigraphic units in the reference sections (Fig. 25). 


This zone is characterized by Pseudofusulinella hidaensis (Kanuma). It is accom 

panied by Fusulina sp. Although Ozawa and Kobayashi (1990) first introduced the 

Pseudofusulinella hidensis Zone, this zone is not confirmed in many areas. The 

Pseudofusulinella hidaensis Zone is correlative with the bed over the Fusulinella Zone. 

Wilde (1971, 1975, 1984) classified Pseudofusulinella into four specific groups (Group 

I: elongate-fusiform species with perched chomata, Group II: small, very slenderfusiform 

species with perched chomata, Group III: intermediate, thickly fusiform 

species with perched chomata, Group IV: large, thickly fusiform species with massive 

chomata). Pseudofusulinella hidaensis (Kanuma) probably belongs to Group I: Species 

with elongate-fusiform shell with perched chomata. This zone is possibly correlated 

with his Zone A and Zone 1 (Wilde, 1984). Ross (1984) noticed that Pseudofusu 

linella is sometimes accompanied by lower Permian Schwagerina, and these species of 

Pseudofusulinella may be relicts of their Carboniferous ancestors. Gobbett (1973) 

emphasized that Pseudofusulinella belongs to an element of the boreal fauna and the 

occurrence is confined to the Lower Permian. Rui, Ross and Nassichuk (1991) 

discussed the paleobiogeography of late Moscovian (Desmoinesian) age and discrim 

inated four climatic zones and fusulinacean provinces. They mentioned that both 

Wedekindellina and Pseudoendothyra are representative of the Arctic province, whereas 

Beedeina, Fusulina, and Neostaffella are characteristic genera of the Tethyan province. 

Beedeina was not found along AK Traverse and JI Traverse, and the problem of the 

faunal province of the Pseudofusulinella hidaensis Zone and its detailed stratigraphic 

position continues to be unclear. However, this zone is possibly correlated with the 

preceding Fusulina-Beedeina Zone and the bed under the Zone 1 and Zone A by Wilde


(1984). 


This zone is characterized by the occurrence of Protriticites matsumotoi (Kanmera). 

The upper part of this zone in the first sequence contains Quasifusulinoides sp. A. The 

distribution of Quasifusulinoides sp. A is definite, so the present zone is tentatively 

subdivided into two zones the lower, the Protriticites matsumotoi Zone (s. s.) and the 

upper, the Quasifusulinoides sp. A Zone. 


This zone is defined by the occurrence of characteristic species, Protriticites 

matsumotoi (Kanmera). This zone is correlative with beds of other areas, bearing 

Protriticites. Davydov (1990) showed a lineage of Fusulinella- Protriticites-Montiparus- 

Rauserites and established the Protriticites pseudomontiparus-Obsoletes obsoletus Zone over 

the Fusulinella bocki-Fusulina eopulchra-Fusulina cylindrica Zone. The Protriticites matsumo 

toi Zone is correlated with the Protriticites pseudomontiparus Zone (Davydov, 1990) from 

the associated fusulinaceans, such as Obsoletes obsoletus (Schellwien). Ross and 

Ross (1985b, 1988) recognized the Obsoletes obsoletus Zone under the Quasifusulinoides- 

Protriticites pseudomontiparus Zone. Ozawa and Kobayashi (1990) also discriminated 

the Obsoletes obsoletus Zone under the Protriticites subschwagerinoides Zone in the Akiyoshi 

Limestone Group. In the AK area, Obsoletes obsoletus (Schellwien) was found 

within the biohorizon of the first appearance of Protriticites matsumotoi (Kanmera). 

Watanabe (1991) established the Obsoletes obsoletus Zone which is correlative with the 

Protriticites matsumotoi Zone (s. 1.). Davydov (1990) proposed that the boundary 

between the Middle and Upper Carboniferous should be drawn at the biohorizon 

which is characterized by the first appearance of Protriticites. Rauser and Shcherbovich 

(1974) drew the boundary between the Moscovian and Kassimovian Stage at 

the lower boundary of the Protriticites Zone. Ross and Ross (1985b, 1988) recognized 

the Fusulina cylindrica-Protriticites ovoides Zone under the Obsoletes obsoletus Zone. 

The present Protriticites matsumotoi Zone (s. s.) is correlative with the lower part of 

the Protriticites pseudomontiparus-Obsoletes obsoletus Zone (Leven, 1979, 1980a, 1981; 

Leven and Shcherbovich, 1978; Winkler, 1990), the lower part of the Eowaeringella 

Zone (Wilde, 1984), the lower part of the Quasifusulinoides, Eowaeringella, Oketaella 

Zone (Ross and Ross, 1985b, 1987, 1988), the lower part of the Protriticites sub 

schwagerinoides Zone (Zhou et al., 1987), the lower part of the Protriticites-Obsoletes 

assemblage Zone (Zhang, 1983, 1991) and the lower part of the Obsoletes-Montiparus 

Subzone (Ding et al., 1991). 


This zone is tentatively defined by the first occurrence of Quasifusulinoides. The 

name Quasifusulinoides was first introduced as Fusulina ex. gr. quasifusulinoides- Quasi 

fusulinoides- Quasifusulina in the table of M. -Maklay, Rauser and Rozovskaya 

(1958). After then, Quasifusulinoides was described by Rauser and Fursenko (1959) 

with Pseudotriticites fusiformis Rozovskaya, 1952 as the type species. Chen (1963)


and Nikitina (1969) treated Quasifusulinoides as a subgenus of Fusulina. M. -Maklay 

(1963) considered this genus as a synonym of Pseudotriticites. According to Thomp 

son (1964), the difference between Quasifusulina Chen, 1934 and Quasifusulinoides 

cannot be recognized. Sheng, Zhang and Wang (1988) noticed that Quasifusuli 

noides should be included in Fusulina. Rozovskaya (1975) treated Quasifusulinoides as 

a valid name, and Pseudotriticites as a synonym of Fusulina. Ueno (1991b) stated that 

Quasifusulinoides could be distinguished from Fusulina by its wall with fine perforation 

and its younger stratigraphic occurrence than the latter. Ginkel and Villa (1991) 

agreed to treat Quasifusulinoides as Fusulina (Quasifusulinoides). In short, the differ 

ences between Fusulina and Quasifusulinoides were treated as those of subgeneric level. 

Collected specimens of Quasifusulinoides sp. A from AK Traverse have advanced wall 

with tectum, "protheca" and inner tectorium, and the wall structure is similar to that 

of the genus Fusulina. Thus Quasifusulinoides is considered to belong to Fusulininae. 

Furthermore, the stratigraphic occurrence is higher than that of Fusulina, because 

Quasifusulinoides sp. A was found above the level of the first appearance of Protriticites 

matsumotoi (Kanmera). As the distribution of this zone is narrow and restricted, 

detailed correlation is difficult. However, Davydov (1990) noticed the coccurrence 

of Quasifusulinoides with Fusulinella and Protriticites, and he proposed the boundary 

between the Middle and Upper Carboniferous at a level of the first appearance of 

Protriticites. Therefore, this zone is correlative with the Protriticites pseudomontiparus- 

Obsoletes obsoletus Zone. Ross and Ross (1985b, 1987, 1988) recognized the Quasifusu 

linoides Zone and Protriticites pseudomontiparus Zone over the Obsoletes obsoletus Zone in 

N. W. Europe, Moscow Basin and southern Ural. The present Quasifusulinoides sp. 

A Zone is correlated with the above Quasifusulinoides Zone and Protriticites pseudomonti 

parus Zone, and more probably with the upper part of the Protriticites pseudomontiparus- 

Obsoletes obsoletus Zone of Russia (Leven, 1980a, b, 1981; Leven and Shcherbovich, 

1978; Winkler, 1990), the upper part of the Eowaeringella Zone of U. S. A. (Wilde, 

1984), the upper part of the Quasifusulinoides, Eowaeringella, Oketaella Zones of the 

southwestern United State (Ross and Ross, 1985b, 1987, 1988), the upper part of the 

Protriticites subschwagerinoides Zone of South China (Zhou et al., 1987), the upper part 

of the Protriticites-Obsoletes assemblage Zone summarized by Zhang (1983, 1991), and 

the middle part of the Obsoletes-Montiparus Zone of North China (Ding et al., 1991). 


The Montiparus sp. A Zone is characterized by the occurrence of Montiparus, and 

correlated with the Montiparus Zone in other areas. Zhang (1984) divided the 

Permian in South China into the following three stages, based on the fusulinacean 

wall structure. 

(1). Pre-keriotheca stage (Fusulina: Dalan Stage). 

(2). Keriotheca stage (Montiparus, Triticites, Pseudoschwagerina, Sphaeroschwagerina, 

Robustoschwagerina: a. Mapingian Stage; Pseudofusulina: b. Xiangzhongian Stage; 

Misellina: c. Qixian Stage; Cancellina, Neoschwagerina, Yabeina: d. Maokouan Stage).


(3). Post-keriotheca stage (Codonofiisiella: a. Sanyangian Stage; Palaeofusulina: b. 

Changxingian Stage). Zhang insisted that the base of the Permian System should 

be placed at the base of (2)-a: Mapingian Stage, and it was reasonable to draw the 

boundary based on the evolutionary stage, i.e. the development of keriotheca, and 

this was suitable for establishing the biostratigraphic boundary. According to 

Zhang (1984), the most primitive fusulinacean with keriotheca is Montiparus, but he 

did not remark on Protriticites. The problems of the "Protriticites-type wall" still 

remain in question. The present zone's leading fossil belongs to Montiparus, and thus 

the zone is correlative with the Lower Permian Mapingian (Zhang, 1984), but the 

correlation based on the first appearanceof keriotheca is very difficult. Ross (1967, 

1973) pointed out that the rapid evolution of fusulinaceans in the Eurasian Arctic 

province had produced a series of early schwagerinid genera such as Protriticites, 

Montiparus, Obsoletes and Triticites. Triticites was considered to be the only genus of 

this series which had successfully invaded in the mid-continent province. In short, 

the genera Obsoletes, Protriticites and Montiparus are representative of the Eurasian- 

Andean province and therefore the direct correlation based on these genera is very 

difficult among the other different faunal provinces. 

The present Montiparus sp. A Zone corresponds to the following biohorizons by 

Wilde (1984): Zone 2, Triticites planus, Eotriticites; Zone 3, Kansanella, Triticites ohioensis; 

Zone 4, Dunbarinella, Triticites beedei- moorei- plummeri, Waeringella, Rauserites}. In 

addition the following zones by Ross and Ross (1985b, 1987, 1988), probably 

correspond to the present zone: the Kansanella (Lowanella) winterensis and Triticites cf. 

ohioensis Zones; the Triticites ohioensis, Triticites collus, and Triticites nebraskensis Zones; 

the Triticites primarius and Kansanella neglecta Zones; the Triticites iatensis, Triticites newelli 

and Kansanella (Kansanella) joensis Zones; the Triticites mcgrewensis and Dunbarinella 

Zones of the southwestern United State. The Montiparus montiparus Zone and the 

Triticites acutus-Triticites quasiarcticus Zone ofRussia (Winkler, 1990), the upper part of 

the Montiparus montiparus Zone and the overlying Triticites acutus-Triticites quasiarcticus 

Zone of Russia (Popov et al., 1985; Chuvashov et al., 1986), the Montiparus montiparus 

Zone and the overlying Triticites acutus-Triticites ardicus Zone in Russia (Leven, 1980a, 

b, 1981; Leven and Shcherbovich, 1978) are also correlative with the present zone. 

The Triticites montiparus Zone in South China (Zhang et al., 1987) and the Montiparus 

range Zone or the Triticites acme Zone of Zhang (1983, 1991) are tentatively cor 

related with the present zone. 

4. Triticites simplex Zone(s. 1.) 

The Triticites simplex Zone (s. 1.) comprises the tentatively discriminated two 

zones: the lower, the Schwagerina sp. A Zone, and the upper, the Triticites simplex Zone 

(s. s.). 

4-(l). 

Schwagerina sp. A Zone 

This zone is characterized by the abundant occurrence of Schwagerina sp. A. 

The stratigraphic significance of the genus Schwagerina was mentioned by many


authors, for example, Dunbar and Skinner (1936), Dunbar (1958), Ross (1963b), 

Skinner and Wilde (1965) and Rauser and Shcherbovich (1970). In 1954, 

opinion 213 designated the type species of Schwagerina sensu Moller, 1877 with 

Borelis princeps Ehrenberg, 1842= Ehrenberg, 1854 sensu Dunbar and Skinner, 

1936, non Schwagerina moelleri Rauser, 1937= Schwagerina princeps (Ehrenberg) sensu 

Moller, 1878. In Japan, many workers use the generic name Schwagerina sensu by 

Dunbar and Skinner (1936, 1937), but internationally, two types and senses for 

Schwagerina are apparently present. In short, two species of the Schwagerina are used 

for the type species, namely Schwagerina moelleri Rauser, 1936 = princeps (Ehrenberg, 

1942) sensu Moller, 1878, and Schwagerina sensu Moller, 1877, based on the 

reexamination of Borelis princeps Ehrenberg by Dunbar and Skinner (1936). Wilde 

(1984) maintained that Rugosofusulina Rauser, 1938 is a synonym of Pseudofusulina 

Dunbar and Skinner, and numerous workers in C. I. S. had included Schwagerina in 

Pseudofusulina. Zhang (1991) noticed that the first appearance of Schwagerina was 

recognized at the base of the Triticites stuckenbergi Zone in Russia. Therefore, the 

present Schwagerina sp. A Zone is correlative with the lower part of the Triticites 

stuckenbergi Zone. Wilde (1984) correlated the Triticites-Schwagerina Zone with a part 

of Triticites (a part of C3b), Rauserites stuckenbergi (C3c), Jigulites (C3d) and Daixina 

(C3e). Sheng, Zhang and Wang (1988) regarded Daixina as a synonym of 

Schwagerina sensu Dunbar and Skinner, 1936. From these facts, the first appeared 

biohorizon ofSchwagerina probably corresponds to the base of'theDaixinafragilis Zone 

(Popov et al., 1985) and the Triticites stuckenbergi Zone in the other area. Rauser 

(1958) subdivided the Triticites arcticus-Triticites acutus Zone under the Triticites 

stuckenbergi Zone into five units as follows: (1) the Triticites irregularis-Fusiella granumoryzae 

unit; (2) the Triticites acutus- Triticites rossicus unit; (3) the Rugosofusulina unit; (4) 

the Triticitesfortissimus unit, and (5) the Triticites praeexilis unit. Ofthem, the Triticites 

irregularis-Fusellagranum- oryzae unit contains Quasifusulina longissima (Moller). From 

the similarity between the obtained Quasifusulina sp. A and Quasifusulina longissima 

(Moller), the present Schwagerina sp. A Zone possibly corresponds to the upper 

Triticites arcticus-Triticites acutus Zone or the biohorizon over the latter zone. How 

ever, Quasifusulina sp. A has a more advanced form than Quasifusulina longissima 

(Moller), and the first appearance of Schwagerina seems to coincide with the lower 

boundary of the Triticites siuckenbergi Zone. Taking this evidence into consideration, 

the Schwagerina sp. A Zone probably corresponds to the Triticites stuckenbergi Zone in 

other areas, or Zone 5, the lower part ofthe Triticites-Schwagerina Zone (Wilde, 1984), 

or the Triticites callosus, Triticites cullomensis and Triticites plummeri Zones (Ross and 

Ross, 1985b, 1987, 1988). 


This zone is characterized by the following fusulinaceans (M. Ota, 1977): 

Triticites simplex (Schellwien), Triticites ozawai Toriyama, Triticites montiparus (Ehren 

berg, 1854) sensu Moller, 1878, non Ehrenberg: Fusulina montipara (Moller, 1878)


sensu Ozawa, 1925, Triticites biconicus Toriyama, Triticites suzukii (Ozawa), Triticites 

noinskyi paula Toriyama, Triticites arctica (Schellwien), Quasifusulina longissima (Mol 

ler) and Schubertella kingi Dunbar and Skinner. The diagnostic species, Triticites 

simplex (Schellwien) was not found along AK Traverse and thus this zone was 

divided by the other diagnostic fusulinaceans. In this paper, the Triticites simplex 

Zone by M. Ota (1977) is divided into three zones, namely, the lower, the Montiparus 

sp. A Zone, the middle, the Schwagerina sp. A Zone, and the upper, the Triticites 

simplex Zone (s. s.). The Montiparus sp. A Zone probably corresponds to the stratigraphically 

lower biohorizon, bearing Triticites montiparus sensu Ozawa and Quasifusu 

lina longissima (Moller). The Schwagerina sp. A Zone is correlated with the 

biohorizon of Triticites biconicus Toriyama. The Triticites simplex Zone (s. s.) corres 

ponds to the biohorizonof Triticites ozawai Toriyama. Therefore, the Triticites simplex 

Zone (s. s.) in this paper is correlated with the upper part of the Triticites simplex Zone 

(M. Ota, 1977), a part of the Triticites-Schwagerina Zone, the upper of Zone 5, and 6 

(Wilde, 1984), and the Triticites subventricosus, Triticites whetstonensis, Schubertella 

whetensis Zones, and the Leptotriticites americana, Triticites ventricosus, Schwagerina cf. 

Schwagerina longissimoidea Zones (Ross and Ross, 1985b, 1987, 1988). 


The datum level of this zone is well defined by the first occurrence of the inflated 

schwagerinid, Pseudoschwagerina. This zone is characterized by Pseudoschwagerina 

muongthensis (Deprat) and the base coincides with the biohorizon bearing Pseudo 

schwagerina morikawai Igo. Hence, this biohorizon is correlated with that of the in 

flated schwagerinids. 

Inflated schwagerinids have been studied by many paleontologists for a long 

time. The following important studies on inflated schwagerinids should be men 

tioned: Dunbar and Skinner (1936, 1937), Dunbar (1958), Rauser (1959, 1960), M. 

-Maklay (1959), Ross (1962, 1963a, b, 1964, 1967, 1972a, 1973, 1982), Tikhvinskiy 

(1965), Rauser and Shcherbovich (1958, 1970), Sheng, Wang and Zhong (1984), 

Davydov (1984), Leven (1987) and Yang and Hao (1991). Dunbar and Skinner 

(1936) defined Schwagerina and established two new genera, namely, Pseudoschwagerina 

and Paraschwagerina. Then, they designated Schwagerina uddeni Beede and Kniker, 

1924, as the type species of Pseudoschwagerina and remarked that the proloculus of this 

genus is commonly large, and the whorls of thejuvenarium are relatively short and 

thickly fusiform (pi. 11, figs. 6 and 7). Original designation of Schwagerina uddeni 

Beede and Kniker included both microspheric and megalospheric forms. Dunbar 

and Skinner (1936, plate 11, figs. 6-7; 1937, plate 50, figs. 1-10; 1937, plate 53, fig. 

8) regarded a typical form ofPseudoschwagerina uddeni (Beede and Kniker, 1924) sensu 

Dunbar and Skinner as a megalospheric form, but Schwagerina uddeni Beede and 

Kniker, 1924 originally includes the microspheric form also. In their description, 

Dunbar and Skinner (1936) expressed as "commonly large" for the proloculus, and 

they implicitly recognized the existence of the microspheric form. Such being the


case, it is preferable that Pseudoschwagerina has both the two types microspheric and 

megalospheric forms. Furthermore, the holotype of Pseudoschwagerina was designated 

by Thompson (1948) with the specimen figured by Beede and Kniker (pi. 6, fig. 1, 

axial section of microspheric form). M. -Maklay (1959) classified Schwagerinidae 

Dunbar and Henbest, 1930 into 10 genera, recognizing Schwagerina Moller, 1877 

and establishing new genera, namely Occidentoschwagerina and Sphaeroschwagerina (in 

1956, Sphaeroschwagerina was originally proposed by M. -Maklay, but no description 

was done.). Rauser and Shcherbovich (1958) recognized both Pseudoschwagerina 

Dunbar and Skinner, 1936 and Schwagerina Moller, 1877. Rauser (1959) treated 

Pseudoschwagerina Dunbar and Skinner, 1936 as distinct from Schwagerina Moller, 

1877 based on the form of each juvenarium. Rauser (1960) subdivided Schwagerina 

Moller, 1878 into five genera, and Zellia Kahler, 1937 into three groups. In 

addition, she established the new genus Parazellia with Fusulina muongthensis Depart, 

1951 (pi. II, fig. 1) as the type species. Rauser and Fursenko (1959) also regarded 

Schwagerina Moller, 1877 as an independent genus and designated Schwagerina 

princeps sensu Moller, 1878 as the type species. Rauser and Shcherbovich (1970) 

discussed characters of Schwagerina Moller, 1877 and they clearly distinguished 

Pseudoschwagerina Dunbar and Skinner from Schwagerina Moller. 

As mentioned before the type species of Schwagerina sensu Moller, 1877 is Borelis 

princeps Ehrenberg, 1842 without doubt. If Schwagerina moelleri Rauser, 1936 and 

Schwagerina moelleri Rauser, 1949 are distinguishable from Schwagerina uddeni Beede 

and Kniker, 1924, a new genus will be established for Schwagerina "moelleri" Rauser. 

Perhaps, the concept of the above new genus corresponds to that of Alpinoschwagerina 

Bensh, 1972. However, Alpinoschwagerina Bensh, 1972 is considered to be a synonym 

of Pseudoschwagerina Dunbar and Skinner, 1936. Sheng, Zhang and Wang (1988) 

distinguished Sphaeroschwagerina M. -Maklay, 1959 from Pseudoschwagerina Dunbar 

and Skinner, 1936 by its having concave pointed poles and small proloculus. 

However, they treated Alpinoschwagerina Bensh as a synonym of Sphaeroschwagerina M. 

-Maklay, 1959. In addition, they emphasized that Schwagerina in Russia is the same 

as Pseudoschwagerina Dunbar and Skinner. According to Loeblich and Tappan 

(1988), Sphaeroschwagerina can be distinguished from Pseudoschwagerina by its short axis. 

To the contrary, Alpinoschwagerina, which was established by its having a much 

smaller proloculus than that of Pseudoschwagerina, practically cannot be distinguished 

from Pseudoschwagerina Dunbar and Skinner, 1936. In a word, Alpinoschwagerina rep 

resents the microspheric form of Pseudoschwagerina. On the other hand, Davydov 

(1984) studied the origin of "Schwagerina" and discussed two lineages, Biwaella- 

Dutkevichites- Sphaeroschwagerina and Biwaella- Biwaella. Then he proposed the sub 

family Biwaellinae, and mentioned that the taxonomic homonym between "Schwager 

ina" and Pseudoschwagerina still continues. Moreover, he pointed out that the 

overestimated "Schwagerina sensu Rauser" should be treated as Sphaeroschwagerina, 

which was applied to the inflated "Schwagerina" of M. -Maklay (1959). Leven


(1987) noticed that among the group of "Schwagerina", Occidentoschwagerina, Para 

schwagerina, Pseudoschwagerina and Zellia appeared in Asselian time, whereas Robusto 

schwagerina in Sakmarian time, and Orientoschwagerina appeared in Murgabian time. 

Additionally, he mentioned about the origin of Schubertellidae Skinner, 1931 and 

agreed with the Davydov's opinion in 1984, in which schubertellid was regarded as 

an ancestor of Biwaella. Davydov (1988b) regarded the occurrence of Schwagerina 

sensu Davydov (1988b) as being at the lower horizon of the Daixina (Ultradaixina) 

postsokensis Zone. 

As a result, the collected megalospheric species at AK 26 along AK Traverse 

was discriminated as Pseudoschwagerina muongthensis (Deprat) because it has a relative 

ly large proloculus, thick spirotheca and inflated outline. Loeblich and Tappan 

(1988) and Sheng, Zhang and Wang (1988) also regarded it as Pseudoschwagerina. 

In the AK area, the collected inflated schwagerinids with microspheric proloculus are 

closely similar to a variation of Pseudoschwagerina morikawai Igo, 1957. Judging from 

the morphology of Pseudoschwagerina, the collected specimen was identifiable as 

Pseudoschwagerina morikawai Igo. The present Pseudoschwagerina muongthensis Zone is 

approximately correlated with the biozone between the first occurrence of inflated 

schwagerinids and the occurrence of typical Pseudofusulina in other areas. 


The characteristic speciesof this zone is Pseudofusulina vulgaris s. s. (Schellwien, 

1909). Internationally, several variations of Pseudofusulina are present. Naoumova 

and Rauser (1964) reported two different types of Pseudofusulina at different stratigra 

phic positions. Rauser (1951) reported a primitive type of "Pseudofusulina" fauna 

from the "Pseudofusulina Horizon" (C3II) under the Schwagerina Horizon (C3III). 

According to this, Pseudofusulina ex. gr. vulgaris Schellwien, 1908, occurs from an 

older horizon than the Schwagerina Horizon. Davydov (1988a, b), reexamined 

pseudofusulinids and discussed their origin. Zhang (1983, 1991) made the bioho 

rizon of the first appearance of the "Pseudofusulina" coincide with the lower boundary 

of the Daixina sokensis Zone. If this is so, Pseudofusulina appears under the Pseudo 

schwagerina Zone. Pseudofusulina was first established by Dunbar and Skinner (1931) 

with Pseudofusulina huecoensis Dunbar and Skinner, 1931 as the type species. Pseudo 

fusulina, at one time, was regarded as a synonym of Schwagerina (Dunbar and Skin 

ner, 1936). Rauser (1937) proposed the new genus Rugosofusulina with Alveoli prisca 

Ehrenberg em. Moeller as the type species. Thompson (1948) designated the 

holotype of Pseudofusulina huecoensis (plate 1, figure 5, Dunbar and Skinner, 1931). 

Rauser (1949) studied Pseudofusulina Dunbar and Skinner, 1931 and referred 

Fusulina moelleri Schellwien, 1908 to Pseudofusulina. Since then, the confusion be 

tween Pseudofusulina and "Schwagerina" has continued. Skinner and Wilde (1965, 

1966) revised the definition of the genus Pseudofusulina, because of the existence of 

rugosity in Pseudofusulina huecoensis Dunbar and Skinner, 1931. At the same time, 

they established the new genus Chalaroschwagerina characterized by having a distinct


phrenothecae. Rozovskaya (1975) treated Rugosofusulina Rauser, 1937 as a valid 

genus, but did not recognized Chalaroschwagerina Skinner and Wilde, 1965 because 

the latter genus was treated as a synonym of Pseudofusulina Dunbar and Skinner. 

Thompson (1964) accepted both Pseudofusulina Dunbar and Skinner and Rugosofusu 

lina Rauser. In Loeblich and Tappan (1988) Rugosofusulina Rauser was treated as 

a synonym of Pseudofusulina Dunbar and Skinner, but Chalaroschwagerina Skinner and 

Wilde, 1965 was treated as valid. Sheng, Zhang and Wang (1988) also recognized 

both Pseudofusulina and Chalaroschwagerina as distinct genera. They additionally 

commented that Chalaroschwagerina has a special form which is distinct from the genus 

Pseudofusulina. They also pointed out that the sense of Pseudofusulina in Russia was a 

mixed one of Schwagerina sensu Dunbar and Skinner (1936) and Pseudofusulina sensu 

Dunbar and Skinner (1931). Consequently, the stratigraphic position and defini 

tion of "Pseudofusulina" are ambiguous and its correlation is very difficult at present. 

According to Leven (1970), the following species are the index fusulinaceans of 

Upper Artinskian time: Misellina (Brevaxina) dyhrenfurtki (Dutk.), Darvasites ordinatus 

(Chen), Darvasites contractus (Schellw. and Dyhr.), Rugosofusulina vulgariformis Kalm., 

Pseudofusulina kraffti (Schellw. and Dyhr.) and Pseudofusulina fusiformis (Schellw. 

and Dyhr.), Pseudofusulina exigua (Schellw. and Dyhr.). Thus, the upper limit of 

the present Pseudofusulina vulgaris Zone becomes older than the base of the Upper 

Artinskian. Leven (1975) insisted that the Sakmarian Stage with robustoschwagerinids 

and paraschwagerinids must be assigned to the deposits in the interval between 

the lower, the Schwagerina Bed and the upper, the Pseudofusulina Bed with Pseudofusuli 

na vulgaris-Pseudofusulina kraffti. Leven (1979) proposed that the Bolorian Stage is 

divided into the upper, the Misellina parvicostata Zone and the lower, the Misellina 

dyhrenfurtki Zone. He mentioned that the Bolorian species, comparing with their 

immediate ancestors, have larger dimensions, and more intense and regular folding of 

septa and cuniculus. Furthermore, he concluded that the characteristic fusulina 

ceans of the Pseudofusulina vulgaris Zone, the Pseudofusulina fusiformis Zone, and the 

Pseudofusulina ambigua Zone (Kanmera and Mikami, 1965a, b), the Pseudofusulina 

ambigua Zone of Toriyama (1958) and the Pseudofusulina kraffti magna Zone, renamed 

by Hasegawa (1963), were similar to those which accompanied misellinids in 

Darvaz, and further more that the Parafusulina kaerimizensis Subzone with misellinids 

(Nogami, 1961) is probably correlated with the Upper Kubergandian Stage. Leven 

(1980b) correlated the Yakhtashian Stage, named after Mt. Yakhtash in Darvaz with 

the Pseudofusulina vulgaris Subzone (Toriyama, 1958). Leven and Shcherbovich 

(1980) pointed out that Pseudofusulina vulgaris (Deprat) is a primitive species regarded 

as Chalaroschwagerina. From these facts and studies, the present Pseudofusulina vulgaris 

Zone probably corresponds to the lower part of the "Chalaroschwagerina" vulgaris Zone 

or the biohorizon under the latter zone (Leven and Shcherbovich, 1978), and the 

Pseudofusulina vulgaris-Laxifusulina iniqua Zone (Zhou et al. 1987), the Pseudoschwagerina 

convexa, Pseudofusulina nelsoni, Schwagerina diversiformis, and Eoparafusulina Zones (Ross


and Ross, 1985b, 1987, 1988). 

-II-4. Conclusion 

The investigated AK area was selected in front of the Akiyoshi-dai Museum of 

Natural History, southern part of the Akiyoshi Plateaus (s. s.). 

Materials from 56 localities were collected along AK Traverse. 15 genera and 

44 species of fusulinaceans were described. Limestones on AK Traverse are mainly 

composed of alternating beds with sparry calcite cements and micritic or micrite 

matrices, and are intercalated with the black to dark brown colored limestones. 

These limestones yield abundant fusulinaceans and algae, and interbedded with them 

are rather coarse limestones containing fragments of crinoids and bryozoans. From 

these studies, the following six zones including tentatively discriminated four zones in 

a narrow sense are recognized along AK Traverse: 1. Pseudofusulinella hidaensis Zone, 

2. Protriticites matsumotoi Zone (s. 1.), 2-(l). Protriticites matsumotoi Zone (s. s.), 2-(2). 

Quasifusulinoides sp. A Zone, 3. Montiparus sp. A Zone, 4. Triticites simplex Zone (s. 1.), 

4-(l). Schwagerina sp. A Zone, 4-(2). Triticites simplex Zone (s. s.), 5. Pseudoschwagerina 

muongthensis Zone, 6. Pseudofusulina vulgaris Zone. The distribution of these zones 

indicates that the limestones in this area have a general northeastern strike and the 

younger zones are successively distributed toward the northwest. Furthermore, the 

limestones along AK Traverse are recognizableas the alternations of limestone of two 

different sequences, probably caused by a fault of NE-SW trend (Ozawa and 

Kobayashi, 1990). In addition, the tentatively discriminated Quasifusulinoides sp. A 

Zone was not identified in the second sequence. The lower part of the overlying 

Montiparus sp. A Zone is composed of limestones with sparry calcite cements 

containing characteristic fusulinaceans similar to those of the underlying zone, 

namely Protriticites matsumotoi (Kanmera). The transitions from Fusulininae or 

Fusulinellinae to Schwagerininae are also recognizable between the Quasifusulinoides 

sp. A Zone or the Protriticites matsumotoi Zone (s. s.) and the Montiparus sp. A Zone. 

Thus, gaps might be present between the underlying Protriticites matsumotoi Zone (s. 1.) 

and the overlying Montiparus sp. A Zone. However, these gaps are interpreted as of 

small scale, because genus level transitions between zones shift gradually as 

mentioned above. The recognized fusulinacean zones were attempted to be corre 

lated with the biostratigraphic zones in the reference sections. The inflated 

schwagerinids have a worldwide distribution and are very useful for international 

correlation of the Upper Carboniferous to Lower Permian. On AK Traverse, the 

Pseudoschwagerina muongthensis Zone was characterized by the occurrence of Pseudos 

chwagerina muongthensis (Depart) and the base of this zone was defined by the first 

occurrence of Pseudoschwagerina morikawai Igo. The author tentatively made the 

basal boundary coincide with the first occurrence of pseudoschwagerinids in other 

areas.


-III-l. The third investigated area, Mt. Maruyama, Mine City, Yamaguchi 

Prefecture 

The third investigated area, Mt. Maruyama, is located in Mine City, Yamaguchi 

Prefecture. In this chapter, the author would like to discuss the phylogenetic 

consideration of the species relative to Protriticites yanagidai Ota and Protriticites 

masamichii Ota from the Mt. Maruyama area. 

,200m- 

Fusulinella simplicata Subzone 

(Kyuma and Nishida, 1987) 

/ 

Fusulinella biconica Subzone 

(Kyuma and Nishida, 1987) 

Yr-~-> 

Profusulinella beppensisZone 


The Mt. Maruyama area is underlain by Middle to Upper Carboniferous 

limestones, and these limestones generally have a northeast strike and a northward 

dip. Furthermore, limestones of this area are regarded as reef facies deposits and 

contain stromatolites and chaetetids (M. Ota, 1968). According to Kyuma and 

Nishida (1987), the following zones are distributed in ascending order: the Profusu 

linella beppensis Zone, the Fusulinella simplicata Subzone and the Fusulinella biconica 

Subzone (Fig. 26). 

The author measured the section along the traverse, namely MA Traverse to 

clarify the localities of the collected fusulinids. Locality MA 66 yields the following 

species: Protriticitesyanagidai Ota, Protriticites masamichii Ota, Protriticites toriyamai Ota 

and Protriticites aff. matsumotoi (Kanmera) mainly obtained from limestones with 

sparry calcite cements. 

Limestones of the Mt. Maruyama area are composed of biomicrite to biomicrudite, 

bryozoa-crinoid biosparite, and shell-crinoid biosparrudite. New species of 

goniatites were described in this area (Kyuma and Nishida, 1987). These sedimen 

tary features suggest that the limestones in this area were formed in a paleoenviron 

ment similar to the reef core in the Akiyoshi organic reef complex. Limestones near 

Loc. MA 66 seem to have accumulated on a reeffiat of a bypass margin between the 

fore reef and open sea, because they yield fragments of ammonoids and fusulinaceans 

(Y. Ota, 1994). 

Form ratio 

2.00 . 

1.00 4.00 

Length 

(mm) 

Fig.27. Each form ratio of the length to width. K: Protriticites afT. matsumotoi. M: Protriticites 

masamichii. T: Protriticites toriyamai. Y: Protriticitesyanagidai.


-III-2. Phylogenetic Consideration 

The collected species, Protriticites yanagidai Ota, Protriticites masamichii Ota, 

Protriticites toriyamai Ota and Protriticites aff. matsumotoi (Kanmera), are characterized 

by their small size, compared to the known species ofProtriticites. Each form ratio of 

the length to widthis shown in Fig. 27. Of these species, Protriticites toriyamai has the 

smallest size shell. Protriticites yanagidai and Protriticites masamichii are almost the 

same in size. Protriticites aff. matsumotoi is about twice as large as Protriticitesyanagidai 

or Protriticites masamichii. Protriticitesyanagidai Ota has a small, fusiform to ellipsoidal 

shell, with slightly and irregularly convex lateral slopes and somewhat sharply 

pointed poles. The present species is closely similar to Protriticites globulus Putrya, 

as the type species of the genus Protriticites. Furthermore, it resembles Protriticites 

matsumotoi, which was first described as Triticites (s. 1.) by Kanmera (1955). There 

fore the phylogenetic line from Protriticites yanagidai Ota to Protriticites matsumotoi 

(Kanmera) is similar to the primitive species of Triticites (s. 1.). On the other hand, 

Protriticites masamichii Ota resembles Montiparus matsumotoi infktus, reported by 

Watanabe (1991) in having moderately inflated, oval to subspherical shell. 

Furthermore, this species is similar to the illustration of Montiparus montiparus shown 

by Rozovskaya (1950). Here, Protriticites masamichii Ota and Montiparus matsumotoi 

infktus of Watanabe (1991) are probably linked together with a phylogenetic line 

(Fig. 28). From these viewpoints, Protriticites yanagidai is considered to be in a 

primitive stage of the phylogenetic lines towards Protriticites matsumotoi, while Protriti 

cites masamichii seems to be a transitional species to Montiparus matsumotoi inflatus. 

In the investigatedJigoku-dani area, the limestones bearing Protriticites masamichii 

in the Protriticites toriyamai Subzone are successively overlain by limestones with 

Protriticites matsumotoi (Kanmera) in the Protriticites matsumotoi Subzone. From this 

field evidence and the morphological affinities, Protriticites matsumotoi is considered to 

be derived possibly from the primitive species of Protriticites, namely Protriticites tori 

yamai, Protriticites masamichii and Protriticitesyanagidai. On the other hand, limestones 

of the Protriticites matsumotoi Subzone are successively overlain by limestones with 

Montiparus sp. A in the Montiparus sp. A Zone at the Jigoku-dani area. In the AK 

area, the Protriticites matsumotoi Zone (s. s.) are overlain by the Montiparus sp. A Zone 

with small gaps, but the limestones are in nearly complete succession. Montiparus sp. 

A is closely similar to Montiparus matsumotoi inflatus of Watanabe (1991). Therefore, 

Montiparus sp. A and Montiparus matsumotoi infktus sensu Watanabe are possibly 

derived from the primitive species of Protriticites, but it is uncertain whether Protriticites 

matsumotoi is directly connected with above species of Montiparus. Incidentally, 

Montiparus matsumotoi inflatus of Watanabe (1991) was mainly reported from the Omi 

Limestone, whereas Protriticites matsumotoi is from the Yayamadake Limestone. The 

above speciations and phyletic transitions might have resulted from the geographic 

isolation between the Akiyoshi Limestone, the Yayamadake and Omi Limestones. 

However, the Akiyoshi Limestone yields these fusulinaceans as mentioned above and

80 

Yasuhiro Ota 

Yayamadake 

Geographic Speciation 

or 

Chronologic speciation 7 

Omi 

Fig. 28. Phylogenetic consideration. 1. Protriticites yanagidai Y'. Ota. 2. Protriticites globulus 

Putrya. 3. Protriticites matsumotoi (Kanmera). 4. Protriticites masamichii Y. Ota. 5, 7. 

Montiparus matsumotoi inflatus, reported from Watanabe (1991). 6. Montiparus montiparus 

from Rozovskaya (1950). 8. Obsoletes obsoletus (Schellwien). 

nearly complete successions of limestones from the Protriticites Zone to the Montiparus 

Zone are confirmed without a remarkable hiatus. Hence, the above speciations and 

phyletic transitions have a great possibility to be the result of chronological speciation. 

Furthermore, the collected species from the Mt. Maruyama area have close 

affinities with Protriticites praemontiparus Zhou, Sheng and Wang, 1987 and Protriticites 

minor Zhou, Sheng and Wang, 1987 from eastern Yunnan, South China. The 

fusulinaceans in the Akiyoshi organic reef complex probably are closely related to 

those of South China during this period.


Consideration 

The purpose of this study is to reexamine the Middle Carboniferous to the 

Lower Permian fusulinacean biostratigraphic units in the Akiyoshi Limestone Group. 

The details are shown in the previous chapters. Here the author would like to 

summarize the paleontology of the Jigoku-dani, AK and Mt. Maruyama areas, which 

respectively contain the characteristic fusulinacean fauna, reflecting slight differences 

of paleoenvironmental character. 

Jigoku-dani area, AK area in front of Akiyoshi-dai Museum of Natural History, 

and Mt. Maruyama area were selected and the field investigations were carried out. 

First investigated area, Jigoku-dani is located in the northwestern part of the 

Akiyoshi Plateau (s. s.). The inverted limestones of Middle Carboniferous to the 

Lower Permian are widely distributed in this area. The studies in this area, lead to 

the following conclusions: The collected materials from the measured sections, JI 

Traverse comprise 56 fusulinacean species including two subspecies and 23 genera. 

From the fusulinacean constituents and distinctions of lithofacies, limestones were 

tentatively divided into nine zones including seven subzones from the Middle 

Carboniferous to the Lower Permian. These zones are well traceable in this area. 

They are as follows: 1. Fusulinella biconica Zone; 2. Fusulina cf. shikokuensis Zone, 2-1. 

Fusulinella cf. obesa Subzone, 2-2. Pseudofusulinella hidaensis Subzone; 3. Obsoletes 

obsoletus Zone, 3-1. Protriticites toriyamai Subzone, 3-2. Protriticites matsumotoi Subzone; 

4. Montiparus sp. A Zone; 5. Triticites yayamadakensis Zone, 5-1. Triticites saurini 

Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconicus Subzone; 6. 

Schwagerina () cf. satoi Zone; 7. Pseudoschwagerina muongthensis Zone; 8. Pseudofusulina 

vulgaris globosa Zone; 9. Pseudofusulina aff. ambigua Zone. Distribution of these zones 

indicates that limestones are inverted in structure. They are composed mainly of 

micritic limestones without frame building organisms. The limestone facies suggest 

that they were deposited in a relatively low energy environment like a lagoon within 

the Akiyoshi organic reef complex. Furthermore, they were successively accumu 

lated without a remarkable hiatus, because no remarkable faunal break could be 

observed in the limestone sequence. Considerable facies changes are present near 

the basal boundaries of the Schwagerina () cf. satoi Zone and the Pseudoschwagerina 

muongthensis Zone. Limestones near the basal boundary of the Schwagerina () cf. satoi 

Zone intercalate fairly coarse grainstones with fragments of reef frame builders and 

the fusulinacean diversity becomes larger across the boundary. Limestones near the 

base of the Pseudoschwagerina muongthensis Zone consist of rather coarse grainstones 

with the sparry calcite cement. In this paper, the author tentatively correlates the 

limestones of the Jigoku-dani area with Middle Carboniferous to Lower Permian 

strata in other areas of Japan and outside Japan by using the first occurrence of the 

inflated schwagerinids, i.e. Pseudoschwagerina. The inflated schwagerinids are very 

useful to correlate the Upper Carboniferous and the Lower Permian, because they are


widely distributed in many regions and are assumed to be planktonic during a part of 

their life cycle. They seem to be excellent index fossils for the correlation of the 

Upper Carboniferous to the Lower Permian. However, they are also known to occur 

in distinctive facies, such as biohermal limestones. Therefore, for regional correla 

tion, examination of the associated fossils along with the inflated schwagerinids is 

indispensable. 

The second investigated AK area is located in front of the Akiyoshi-dai Museum 

of Natural History. AK Traverse was measured and fossils collected along the 

traverse. From the paleontological and lithological viewpoints, the following fusu 

linacean zones are tentatively discriminated in ascending order: Pseudofusulinella 

hidaensis Zone, Protriticites matsumotoi Zone (s. s.), Quasifusulinoides sp. A Zone, 

Montiparus sp. A Zone, Schwagerina sp. A Zone, Triticites simplex Zone (s. s.), 

Pseudoschwagerina muongthensis Zone and Pseudofusulina vulgaris Zone. Detailed field 

mapping of the area revealed two limestone sequences cut by a fault of northeastern 

trend in this area. Limestones appear to have accumulated in a marginal lagoon 

environment in the Akiyoshi organic reef complex. 

The Mt. Maruyama area in Mine City, Yamaguchi Prefecture, is the third 

investigated area. The limestone facies of this area indicate that the paleoenviron 

ment is probably a true reef within the organic reef complex. Loc. MA 66 was 

examined in detail and the following fusulinaceans were identified: Protriticites 

yanagidai Ota, Protriticites masamichii Ota, Protriticites toriyamai Ota and Protriticites aff. 

matsumotoi (Kanmera). These species are characterized by having rather small shell, 

as compared with the known species of Protriticites. From their morphological 

characters, two phylogenetic lines were shown among the primitive Triticites (s. 1.). 

The first line is from Protriticites yanagidai Ota to Protriticites matsumotoi (Kanmera). 

The second one is from Protriticites masamichii Ota to Montiparus matsumotoi infktus, 

reported by Watanabe (1991). From hypothesis based on the morphological 

affinities, Protriticites yanagidai seems to be a primitive stage in the first line, whereas 

Protriticites masamichii is considered to be a transitional species in the second line. 

The transition from Protriticites masamichii to Protriticites matsumotoi in association with 

Protriticites toriyamai is successively confirmed in the Protriticites toriyamai Subzone to 

the Protriticites matsumotoi Subzone in the Jigoku-dani area. Therefore, Protriticites 

matsumotoi (Kanmera) seems to be linked to the above primitive species of Protriticites. 

Furthermore, the Montiparus sp. A Zone, though small gaps were present, conform 

ably overlies the Protriticites matsumotoi Subzone or Zone along AK and JI Traverses. 

Therefore, the relevant species of Montiparus sp. A and Montiparus matsumotoi infktusof 

Watanabe (1991) are probably linked to the primitive species of Protriticites, but it is 

doubtful whether Protriticites matsumotoi (Kanmera) is directly connected with Monti 

parus matsumotoi infktus sensu Watanabe, because of its morphological characters. In 

addition these fusulinaceans are closely similar to Protriticites praemontiparus Zhou, 

Sheng and Wang, 1987 and Protriticites minor Zhou, Sheng and Wang, 1987,


respectively from eastern Yunnan, South China. The examinations of the fusulina 

cean affinities between China and Japan are very important for studying paleobiogeography 

during Carboniferous-Permian time. 

The tentative divisions of the fusulinacean zones proposed for the Middle 

Carboniferous and Lower Permian Akiyoshi Limestone Group and the relevant 

sections are shown in Fig. 17. As mentioned before, it is very difficult to obtain a 

consensus on the leading and index fusulinaceans of each zone even in the Akiyoshi 

Limestone. This seems to be caused mainly by the differences of the original 

habitats and the fusulinacean ecological adaptations and has a close relationship with 

the paleoecology in the Akiyoshi organic reefcomplex (e.g. M. Ota, 1968; Nagai and 

M. Ota 1980; Nagai, 1985). M. Ota (1977) already mentioned that habitat 

segregation is observable with the fusulinacean distribution in the Akiyoshi Lime 

stone, namely Pseudofusulina kraffti magna Toriyama in the lagoonal facies and 

Pseudofusulina ambigua (Deprat) in the sand facies of the reef flat environment. 

The following paleoecology studies were well known before. Ross (1961, 1965, 

1969, 1972b) tried to establish biostratigraphic zones, by considering their paleoen 

vironment. 

He remarked that fusulinaceans lived on the surface of the substratum 

and have adapted to the influence of water conditions, such as temperature, salinity, 

currents and turbidity. Ross (1964) suggested that the morphological changes were 

due to ecological adaptation, for example, the inflated schwagerinids occur in specific 

rock types, such as patch reef accumulations or bioherms. Tikhvinskiy (1965) 

insisted that the elongated and fusiform genera of Schwagerininae were undoubtedly 

bottom dwellers, but some genera with inflated form probably had a planktonic 

habit. Menner (1971) criticized the above opinions because it was very difficult to 

confirm whether the genus "Schwagerina" is planktonic or benthonic. Ross (1972b) 

reconstructed the isolated bioherms in the lower Wolfcampian Neal Ranch Forma 

tion, and discussed the fusulinacean habitats. According to him, the inflated 

schwagerinids, including Pseudoschwagerina uddeni (Beede and Kniker), have a 

distribution near the biohermal buildups and on associated debris aprons. More 

over, Ross (1982) insisted that some genera in the inflated schwagerinids had a 

planktonic phase in the life cycle. Ross and Ross (1988) and Seslavinskiy (1991) 

made it clear that during late Carboniferous and early Permian time, transgression 

shifted to regression. Furthermore, Ross and Ross (1988) suggested that the 

sedimentary environment from the base to upper part of the Wolfcampian changes 

from shelf to basin. Sea level changes may closely relate to the worldwide dispersal 

of the inflated schwagerinids. 

The sedimentary environments of the Akiyoshi Limestone Group in the investi 

gated AK Traverse were, as a whole, reconstructed as like a marginal lagoon within 

the Akiyoshi organic reef complex. The Jigoku-dani area is recognizable as a 

relatively low energy environment like a lagoon. The Mt. Maruyama area, on the 

contrary, reveals an environment near the reef core, according to the biofacies and


lithofacies. 

Along AK Traverse, well preserved Pseudoschwagerina were obtained from micritic 

limestone. The collected specimens of Pseudoschwagerina from AK Traverse, are 

considered to be preserved in the original living position and form. Machiyama and 

Kawamura (personal communication), examined the biohorizon of Pseudoschwagerina 

along AK Traverse and concluded that the energy level of that environment was very 

low because of abundant occurrence of wackestone. In contrast with the AK area, 

Pseudoschwagerina in theJigoku-dai area rarely occurs in limestones with sparry calcite 

cements and is poorly preservation. Under high energy condition, Pseudoschwagerina 

seems to be difficult to preserve well, because of its thin and not very strong walls. 

Pseudoschwagerina in the Akiyoshi organic reef complex probably chose its habitat in 

the marginal lagoon environment and sometimes extended into the central environ 

ment of the lagoon. 

The Triticites-Schwagerina Zone (s. s.) outside the Akiyoshi region, approximately 

corresponds to the Triticites yayamadakensis Zone and the Triticites simplex Zone along 

AK and JI Traverses. These zones in the investigated areas are typified by 

dominance of Triticites (s. s.) and are also characterized by abundance of Schwagerina 

sp. A along two traverses. Triticites yayamadakensis Kanmera is abundant and easily 

traced in the Jigoku-dani area, but this species is rare along AK Traverse. Triticites 

ozawai Toriyama, a closely related species to Triticitesyayamadakensis Kanmera occurs 

along AK Traverse. Fusulinacean constituents of these zones along AK and JI 

Traverses are slightly different, but the above zones also yield many mutual 

fusulinaceans. 

The Montiparus sp. A Zone is confirmedin both AK and Jigoku-dani areas. The 

lower part of the Montiparus sp. A Zone along AK Traverse is accompanied by the 

underlying diagnostic Protriticites matsumotoi (Kanmera). This species might be 

regarded as a member of a "ghost fauna" or the mixed fauna derived from various 

zones, resulting from condensation by sea level changes. Hence, gaps are possibly 

present between the overlying Montiparus sp. A Zone and the underlying Quasifusuli 

noides sp. A Zone in the Protriticites matsumotoi Zone (s. 1.). Furthermore, the horizon 

of the gaps coincides with the biohorizon, changing from Fusulininae or Fusulinell 

inae to Schwagerininae. Consequently the geological event, suggested by the gaps, 

is considered to play an important role in the transition from Fusulininae or 

Fusulinellinae to Schwagerininae. However, Ross (1989) has already pointed out 

that the time for fusulinacean transitions in such a condensed section is too short to 

be reason for the evolution of fusulinaceans. Therefore, the rapid transitions from 

Fusulininae or Fusulinellinae to Schwagerininae observed along AK Traverse are 

dependent on the original evolutionary cause, which fusulinaceans possess rather 

than that caused by paleoenvironmental change. Hasegawa (1963, 1988) discussed 

the origin of the black sparry calcite limestone near the boundary between the 

Carboniferous and Permian. According to him, the datum level of the lower limits


of the black sparry calcite limestone coincides with the biohorizon, where the 

Fusulina-Fusulinella fauna extinguishes, and the new Triticites (s. 1.) fauna appears. 

From its chemical composition, this black to dark brown color limestone is not 

dolomitic, and changes of sedimentary environments are suggested (Musashino, 

Hikabe and Arai, personal communication). It is possible that the black to dark 

brown color limestone along AK Traverse is the product of a geological event, that 

took place after the limestone accumulations of the Quasifusulinoides sp. A Zone. 

The Protriticites matsumotoi Zone in the investigated areas was first introduced by 

M. Ota (1977) as the Triticites (s. 1.) matsumotoi Zone, and is characterized by 

primitive species of Triticites (s. 1.), such as Protriticites matsumotoi (Kanmera). In 

connection with this zone, Minato, Kato, Nakamura, Niikawa and Hasegawa 

(1984) reported that Protriticites matsumotoi (Kanmera) was widely found in Southwest 

Japan. Hasegawa (1988) also reported that the Triticites simplex fauna partly 

overlies in occurrence the rather primitive Triticites (s. 1.) fauna, such as Protriticites 

matsumotoi fauna. He assumed that the primitive Triticites (s. 1.) was probably able to 

settle only in the area, where conditions suitable for fusulinacean recovery arrived 

early in the environmental change. Of the study areas, AK Traverse and JI 

Traverse are supposed to be the presumably recovered areas for them, because a 

rather primitive Triticites (s. 1.) fauna, such as Protriticites matsumotoi fauna, was found. 

The Fusulina-Fusulinella Zone, comparable with the Beedeina akiyoshiensis Zone of 

M. Ota (1977) was not confirmed along AK Traverse and in the Jigoku-dani area. 

Beedeina akiyoshiensis (Toriyama) is known in limestones with sparry calcite cements, 

accumulated in a reef environment. Therefore, it is suggested that Beedeina 

akiyoshiensis (Toriyama) originally could not live in a relatively low energy environ 

ment like along AK and JI Traverses, where the central to marginal lagoon 

environment was predominant. 

As mentioned above, in the Akiyoshi Limestone Group the Middle Carbonifer 

ous and Lower Permian fusulinaceans of each zone are slightly different in their com 

position in different areas. This fact suggests that some fusulinaceans have distinc 

tive habitats different from others in the Akiyoshi organic reef complex. These 

distributional characters control the local bio-divisions and fusulinacean zonations. 

Hence, the analysis of the fusulinacean assemblages, relating to their special 

distribution habitat in the Akiyoshi organic reefcomplex, is essential to establish the 

detailed biostratigraphic division in the future. 

The establishment ofdetailed biostratigraphic units is very important for making 

clear the process of formation of the Akiyoshi organic reefcomplex and is essential to 

learning the paleogeography of Japan in late Paleozoic time. In this connection, 

Hill (1973) referred to the relation between the sedimentary environment of the 

organic reef and the paleolatitude. In fact, Japanese Islands in late Paleozoic time 

was formerly illustrated in many paleogeographic maps nearly at the north latitudeof 

60° in the Arctic region (e.g. Smith et al. 1973; Boucot and Gray, 1980). Taking


the Akiyoshi organic reef complex (e.g. M. Ota, 1968; Nagai, 1978, 1979; Sugiyama 

and Nagai, 1990) and modern coral reef into consideration, the above location of the 

late Paleozoic Japanese Islands, including Akiyoshi region, is unsuitable with present 

knowledge. Ross and Ross (1985a) and Scotese and Mckerrow (1990) showed the 

location of the Japanese Islands in late Paleozoic time near the equator. Their 

conclusions agree with the results of the present study. 

With regard to the changes of fusulinacean genera along AK and JI Traverses, 

the following generic transitions are confirmed: Pseudofusulinella- Protriticites- 

Montiparus- Triticites (Schwagerina)- Pseudoschwagerina- Pseudofusulina. The genus 

Pseudofusulinella was first introduced by Thompson (1951) and is considered to have 

originated from Fusulinella, in the Eurasian Arctic faunas at about the end of late 

Carboniferous time (Ross, 1973). According to Rui, Ross and Nassichuk (1991), 

the Tethyan province, namely tropical and subtropical climatic zones, is marked by 

the transitional series of Fusulinella-Neostaffella-Beedeina-Fusulina fauna. Therefore, 

during the period of the Pseudofusulinella Zone, corresponding to the Fusulina and 

Beedeina Zones, the Akiyoshi organic reef complex was formed in a subtropical and 

tropical environment rather than just an area with a warm temperature. Addi 

tionally, the faunal transition from the Protriticites Zone to the Montiparus Zone was 

confirmed along AK and JI Traverses. As respects Triticites (s. 1.), many authors, 

for examples, Davydov (1990) and Ginkel and Villa (1991) have discussed it 

before. The successive transition from Protriticites to Montiparus has been confirmed 

in the Tethyan province but not in the Mid-continent province. Hence, the Tethyan 

faunal province during the time from the Protriticites matsumotoi Zone to the Montiparus 

sp. A Zone seems to have little connection with that of the Mid-continent faunal 

province. The Pseudoschwagerina muongthensis Zoneis characterized by the widespread 

genus, Pseudoschwagerina. This genus is considered to be planktonic during a part of 

its life cycle. In a strict sense, the development of the Pseudoschwagerina muongthensis 

fauna in the Akiyoshi Limestone Group possibly has a time lag in comparison with 

that of Pseudoschwagerina uddeni (Beede and Kniker) in the Mid-continental province, 

because the pseudoschwagerine faunas arose in western NorthAmerica and after that 

they dispersed and migrated into the Tethys ocean. However, this dispersal time 

was short and we can adapt synchronism to the migration rapidity of Pseudoschwager 

ina. This is the reason why Pseudoschwagerina is very useful for worldwide correlation. 

The next overlying Pseudofusulina Zone is characterized by a cosmopolitan genus, 

Pseudofusulina. However, the stratigraphic distribution and definition of this zone are 

still left in question. 

Acknowledgments 

The author expresses his grateful thanks to Professor Juichi Yanagida, Kyushu 

University, who kindly read the manuscript and offered many helpful suggestions to

Fusulinacean Biostratigraphyof the Akiyoshi Limestone Group, Part I 87 

accomplish this study. Cordial thanks are due to Professor Hakuyu Okada and 

Associate Professor Akihiko Matsukuma, Kyushu University, for reading the 

manuscript and their giving the author helpful criticisms and suggestions during the 

course of this study. The author also wishes to express his grateful thanks to 

Professor Kimiyoshi Sada, Hiroshima University, who kindly read the manuscript 

and provided many suggestions about fusulinaceans. Dr. Kametoshi Kanmera, 

Professor Emeritus, Kyushu University gave him many valuable comments and 

helpful suggestions on the fusulinacean paleontology. Dr. Wilbert R. Danner, 

Professor Emeritus, University of British Columbia, kindly read the manuscript and 

made minor changes in grammar and syntax where needed, and provided useful 

comments and suggestions. Dr. Masamichi Ota, Director of the Kitakyushu 

Museum and Institute of Natural History critically read the manuscript and offered 

many valuable comments and helpful suggestions. The author thanks the following 

persons for their kind help in giving him facilities in field work and valuable 

suggestions; Professor Tamio Nishida, Saga University, Assoc. Prof. Koichi Nagai, 

Ryukyu University, Assoc. Prof. Testuo Sugiyama, Fukuoka University, Dr. 

Kyoichiro Ueda, Curator of the Kitakyushu Museum and Institute of Natural 

History, Messrs. Akihiro Sugimura and Takehiko Haikawa, Akiyoshi-dai Museum 

of Natural History and Mrs. Yuko Kyuma, Primary School of Nagasaki Prefecture. 

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