Arkell.1956.Jurassic..

49° RUSSIA AND THE EUROPEAN ARCTIC
(Neaverson) (pi. xvi), and Allovirgatites ianschini (pis. xviii, xix). In
addition there are fragments of Pectinatites (pis. ix, x, fig. 23, xiii, fig. 27,
the last aff. pectinatus Phil, sp.?) and the coarse-ribbed Wheatleyites
(pi. xiv, X o-8). The Vetlianka Sandstone therefore represents the Subplanites
and Pectinatus Zones of Dorset. To raise it to the rank of 'Wetlianian
Stage' (I. & F., 1941, p. 188) is unnecessary.
In the basins of the upper Ural and Ilek Rivers the Vetlianka Sandstone
rests on beds with Virgataxioceras fallax (Ilovaisky & Florensky, 1941,
pis. ii, iii, and Semenov, 1896, pi. iv, fig. 14), a collective species, some
forms of which are almost identical with V. setatus (Schneid), of the Beckeri
Zone of Franconia. Ilovaisky & Florensky rightly correlated these beds
with the Beckeri Zone.
LOWER KIMERIDGIAN
Next below are the Gorodistche Clays of the Pseudomutabilis Zone,
crowded with Exogyra virgula and ammonites of the genera Aulacostephanus
and Aspidoceras, as in England and western Europe (Pavlow,
1886) (Zone of Aulacostephanus kirghisensis d'Orb., sp., the type of which
came from Saragula, Orenburg). Besides a remarkable series of species
of these two genera, there are several species of Amoeboceras (Pavlow,
pi. viii, figs. 4, 5), Prionodoceras (pi. v, fig. 4), Streblites (pi. viii, figs. 6, 7)
and Torquatisphinctes (pi. viii, fig. 3, ? pi. vii, fig. 3). (PI. vii, fig. 4, seems
to be a Virgataxioceras cf. fallax I. & F. sp., presumably from the overlying
zone). These 'Acanthicus Beds' include also the Tenuilobatus Zone, as
is shown by a number of the ammonites figured by Pavlow.
UPPER OXFORDIAN
Beds on the Oxfordian-Kimeridgian boundary, equivalent to the
Pseudocordata Zone, are represented by Ringsteadia kurmani (I. & F.)
(1941, pi. i, fig. i, = R. aff. marstonensis Salfeld) and Dichotomoceras
sublacertosus (I. & F.) (pi. i, fig. 2). These beds form the top of Nikitin's
comprehensive 'Alternans Zone', and it may be suspected that farther
west they yielded Prionodoceras jasikowi Pavlow sp. (1886, pi. v, fig. 4).
The rest of the Upper Oxfordian is much more fully known in the
Moscow basin (see p. 496).
LOWER OXFORDIAN
Ammonites of this age cited by Sinzow (1899) include Goliathiceras
goliathum, Cardioceras cordatum, 'vertebrale', rouillieri, quadratoides,
Peltoceras arduennense, subconstanti, Aspidoceras perisphinctoides, Grossouvria
miranda, also Scarburgiceras praecordatum and Q. mariae (Sinzow,
1899, as interpreted by R. Douville, 1912, p. 258).
UPPER CALLOVIAN
The Lamberti Zone is conspicuous, with numerous Quenstedtoceras
of the subgenera Lamberticeras, Eboraciceras, and Quenstedtoceras s.s.,
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