Arkell.1956.Jurassic..

THE CAUCASUS 361
(Neumayr & Uhlig, 1892, p. 52). Probably from the same zone comes
Indosphinctes abichi (Neumayr & Uhlig), a link with Cutch and Anatolia.
In Daghestan (Renz, 1904, p. 85) the Middle Callovian represents the
highest part of a thick series of black shales with nodules, which extends
down unchanged into the Toarcian and is one of the most characteristic
features of a vast area. These beds are locally developed as impure
limestones which yield Erymnoceras, Kosmoceras, etc. (Kazansky, 1909).
LOWER CALLOVIAN
Calloviense and Koenigi Zones. Species of Kepplerites and Proplanulites
were already figured by Neumayr & Uhlig (1892, pi. iii, fig. 4,
pi. iv, fig. 1), who also recorded Cadoceras spp. and Chamoussetia
chamousseti (d'Orb.). In the north slopes of the Caucasus the beds
belonging to these zones have been separated from the Middle Callovian
(Nikshick, 1915), but separation from the Macrocephalus Zone has not
yet been attempted. Some and perhaps all the Macrocephalitids figured
from Georgia (Radcha) by Djanelidze (1932), however, are late forms of
the Koenigi Zone. M. colchicus Djan. (pi. vi, fig. 3) is a typical Pleurocephalites
which might easily have come from Cocklebury Hill, Chippenham,
from the Kellaways Clay. This and (for some of the beds) an even
later dating is borne out by the associated Cadoceras, Reineckeia and
Choffatia spp. figured (pi. iii, figs. 3-5). The Aspidoceras (pi. i, fig. 2),
however, must be Upper Callovian; and it comes from a different
locality.
Macrocephalus Zone. The existence and strong representation of this
zone in at least the northern Caucasus is put beyond doubt by two plates
of photographs published by Ilyin (1932). These show typical Dolikephalites
typicus Blake, var. balkarensis Ilyin, Macrocephalites sensu stricto
(pi. ii, fig. 1, 2) and Kamptokephalites (pi. ii, fig. 3), all of which might
have come from the English Upper Cornbrash.
BATHONIAN
The black shales with nodules in Daghestan probably span the whole
Bathonian, but so far few ammonites have been collected that can definitely
be so dated, and of these none has been figured. From Guli, Renz (1913,
p. 690) lists Parkinsonia ferruginea (Oppel) and Lissoceras psilodiscus
(Schloenb.) which indicate Lower Bathonian, Perisphinctes moorei Oppel
which may be a Procerites, also Cadomites rectelobatus (Hauer), Phylloceras
kudernatschi Hauer and Lytoceras adeloides (Kud.). Neumayr & Uhlig
(1892, p. 88) have a similar list from Gunib, but the Stephanoceras they
figure (pi. v, fig. 3, pi. vi, fig. 2) is not C. rectelobatus (Hauer), from which
it differs by its steadily enlarging ribs, which are still becoming blunter
and more distant on a septate whorl; this is no doubt a Bajocian form.
Neumayr & Uhlig (p. 103) admitted that their material did not warrant
any attempt to distinguish Bathonian from Bajocian.
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