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Arkell.1956.Jurassic..

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[VALANGINIAN<br />

THE ANDES OF SOUTH AMERICA 58l<br />

To this stage Leanza (1945) assigns two zones: Neocomites wichmanni<br />

Leanza below and Olcostephanus curacaoensis (Weaver) above, the latter<br />

with Lissonia riveroi (Lisson), which occurs in equivalents of part of the<br />

Mulichinco formation (Weaver, 1931, p.^57).]<br />

[BERRIASIAN<br />

Mulichinco formation. In central and south central Neuquen this<br />

consists of an average thickness of 500 m. of sandstones, conglomerates<br />

ARGENTINA<br />

Zones after Leanza<br />

Spiticeras damesi<br />

Argentiniceras<br />

noduliferum<br />

TITHONIAN—UPPER<br />

Substeueroceras<br />

koeneni<br />

Corongoceras alternans<br />

TITHONIAN—MIDDLE<br />

Windhauseniceras<br />

internispinosum<br />

Pseudoli ssoceras<br />

zitteli<br />

TITHONIAN—LOWER<br />

Virgatosphinctes<br />

mendozanus<br />

TABLE 24.—CORRELATION TABLE FOR THE TITHONIAN OF<br />

SOUTH AMERICA AND MEXICO<br />

MEXICO EUROPE STAGES<br />

Spiticeras beds Berriasella boissieri Berriasian<br />

Substeueroceras<br />

koeneni beds<br />

(with Micracanthoceras,<br />

Proniceras, etc.)<br />

Durangites and<br />

Kossmatia beds<br />

Virgatosphinctes and<br />

Aulacosphinctoides<br />

beds<br />

Subplanites<br />

burckhardti<br />

Mazapilites with<br />

Hybonoticeras<br />

Virgatosph. f chaperi<br />

transitorius ( delphinensis<br />

giganteus )<br />

gorei |<br />

albani<br />

pallasioides<br />

fGap in south<br />

rotunda 1<br />

ciliata/pectinatus<br />

vimineus/Subplanites<br />

ulmense ) ^<br />

, •., , • } Gravesiae<br />

hthographica J<br />

i H. beckeri beds Hybonoticeras beckeri<br />

Ardescian and<br />

Purbeckian<br />

Portlandian<br />

Upper and<br />

Middle<br />

Kimeridgian<br />

and red shale, of continental origin, but northward it is replaced by marine<br />

shales and limestones with ammonites, and is reduced to 200 m. Farther<br />

north, in Mendoza, continental beds die out entirely and the shalelimestone<br />

series is unbroken from Tithonian to Hauterivian or higher<br />

(Weaver, 1931). Leanza (1945, 1947) recognizes two zones:—<br />

Zone of Spiticeras damesi (Steuer) and Cuyaniceras transgrediens (Steuer),<br />

with abundant Cuyaniceras spp. (= Odontoceras auct. = Steueroceras<br />

Cossmann), Neocomites spp., Thurmanniceras spp., Spiticeras spp. and<br />

Pseudoblanfordia australis (Burckh.).<br />

Zone of Argentiniceras noduliferum (Steuer), with Berriasella laxicosta<br />

(Steuer), Frenguelliceras spp., Neocosmoceras egregium (Steuer), Substeueroceras,<br />

Groebericeras, etc.]<br />

http://jurassic.ru/

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