Arkell.1956.Jurassic..

364 RANGES OF SOUTH-WEST ASIA
there are thin marine intercalations. The earliest ammonite horizon
known to Neumayr & Uhlig (1892) yielded abundant Amaltheus margaritatus
and what appears to be a Galaticeras (pi. iii, fig. 3). A lower
bed with Cardinia cf. philea d'Orb. and other lamellibranchs was also
thought to be Pliensbachian or highest Sinemurian by these authors and
by Renz (1904, p. 84), but Oswald (1914, p. 13) assigned it to the
Hettangian. He added that the coal series lies unconformably on the
Palaeozoic schists and contains pebbles of them in its basal conglomerate.
The same is true in the Little Caucasus, where there is a massive basal
conglomerate resting on Lower Palaeozoics (Leontyev, 1950).
In the eastern Caucasus, according to Golubyatnikov (1940) the
enormously thick Toarcian shales rest upon 3000 m. of strongly metamorphosed
shales known as 'Slates of the Main Ridge', in the upper part
of which occur Upper Pliensbachian ammonites of the Apennines:
Arieticeras exiguum (Fucini), A. falciplicatum (Fucini), Fuciniceras bonarellii
Fucini. From this he infers that the lower parts of the slates represent
earlier divisions of the Lias. Oswald (1914, p. 13) also states (following
Abich) that in Daghestan the lower parts of the Lias are represented
by unfossiliferous calc-schists, argillaceous schists and crystalline limestones.
It seems more probable that the metamorphic rocks are Triassic
as suggested by Renz (1913, p. 702) and received their metamorphism
in a pre-Rhaetian orogeny.
TRANS-CASPIA
The minor mountain and hill ranges on the east side of the Caspian
Sea, on the peninsula of Mangyshlak and at Touar-Kyr, lie in Asia and
may be outer ripples of the great ranges of SW. Asia, but they are generally
considered a continuation of the folds of the Donetz (Arkhangelsky &
Schatsky, 1933). They consist essentially of anticlines of Jurassic and
Triassic beds, planed before the Upper Cretaceous and re-elevated in the
Tertiary (fig. 52).
Most of the Jurassic is represented. The series begins with quartzose
conglomerate and continental sandstones containing plants and coal-seams,
probably representing the Lias, as in the Elburz (see below). The first
marine horizon known is Upper Bajocian, with Parkinsonia and Ostrea
acuminata Sow. The Parkinsonia (Eichwald, 1871, pi. I, figs. 6, 7, and
Semenow, 1896a, p. 124) was confirmed by Borissjak (1908, p. 90), but
the supposed Oppelia subradiata (Semenow, 1896a, pi. ii, fig. 1) is a
Callovian Hecticoceras (Sublunuloceras) cf. lahuseni Tsyt. (cf. Couffon,
1919, Callovien du Chalet, pi. xiv, fig. 5). The Callovian is the bestknown
stage as regards ammonites; from it have been figured Macrocephalites
pila Nikitin (Semenow, 1896a, pi. ii, fig. 2), Catasigaloceras sp.
(pi. ii, fig. 6), Kepplerites sp. (pi. iii, fig. 2), Reineckeia and Proplanulites
(pi. ii, figs. 5, 7), Choffatia (pi. iii, fig. 3) and Pseudopeltoceras (pi. iii,
fig. 5), Kosmoceras, Quenstedtoceras, etc. The Lower Oxfordian is represented
by Goliathiceras andrussovi Sem. sp. (pi. ii, fig. 3). There follows
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