Arkell.1956.Jurassic..

LOWER OXFORDIAN
RUSSIA 497
Cordatum Zone. Bed Ai, with Cardioceras ilovaiskyi Maire (Ilov.,
pi. x, fig. 28) and other forms of the cordatum group (pi. x, fig. 31),
Goliathiceras sp. (pi. x, fig. 27), Pachycardioceras rouilleri (p. 268) and
Perisphinctids. Other ammonites of the Cordatum Zone were figured by
Lahusen (1883): C. cordatum (Sow.) (pi. v, fig. 5), C. costicardia (Buck.)
(pi. v, fig. 3), Aspidoceras aff. catena (Sow.) (pi. x, fig. 14), Peltoceratoides
sp. (pi. x, fig. 12).
Mariae Zone. Bed K contains Quenstedtoceras (Pavloviceras) pavlowi
Douville, of which the type came from Ryazan, and allied species
(Ilovaisky, pi. x, figs. 22-25; Lahusen, 1883, pi. iv, figs. 6-17). To the
same zone belongs Cardioceras (Scarburgiceras) lahuseni Maire (Lahusen,
1883, pi. v, fig. 1). At Miatchkovo near Moscow, this zone rests on
Carboniferous Limestone, which is quarried on both banks of the Volga.
UPPER CALLOVIAN
The Lamberti Zone is strongly represented on the Upper Volga and in
the Ryazan province by the Leachi Zone of Nikitin, with a range of
Quenstedtoceratids comparable with those in the Hackness Rock and the
Lamberti Limestone at Woodham pit in England. The clay of this zone
similarly passes into a band of argillaceous limestone in places on the
upper Volga; and at Novosselki in Ryazan province it oversteps on to
Carboniferous Limestone. A notable link with England is the presence
of conspicuous large Eboraciceras, to which belong Q. rybinskianum
Nik. (1881, pi. i, fig. 8) and Q. problematicum Sinzow, 1899 (type, Nikitin,
1881, pi. i, fig. 6), together with Lamberticeras (pi. i, fig. 1, and Lahusen,
1883, pi. iv, figs. 1-3, and perhaps fig. 4, the type of Q. pseudolamberti
Sinzow, 1899), Prorsiceras (Nikitin, 1881, pi. i, fig. 5), Pachyceras mologae
Nikitin sp. (pi. i, fig. 12), and the ubiquitous Kosmoceras spinosum Sow.
sp. (pi. iv, fig. 34) and K. proniae and its allies (Teisseyre, 1884). The
last and K. transitionis Nik. and various Peltoceratids (Lahusen, 1883,
pi. x, figs. 5-9) indicate that the Athleta Zone is represented. Various
well-preserved Hecticoceratids come from the Upper and Middle Callovian
(Lahusen, pi. xi).
MIDDLE CALLOVIAN
The Coronatum and Jason Zones are widespread and are represented
by Lahusen's beds b, c. They yield Erymnoceras coronatum and E. doliforme
Roman (Neumayr, 1876, pi. xxv, figs. 1-3; Lahusen, 1883, pi. vi, figs. 1-4)
and numerous appropriate Kosmoceras, Hecticoceras, etc. (Lahusen,
pis. vii-xi). Presumably from this level also comes Erymnoceras renardi
Nikitin sp. (1882, pi. xi, fig. 24). At Sergatch the Coronatum Zone with
Erymnoceras is developed as a band of oolite (Milachewitch, 1880).
Classic works, chiefly based on ammonites from this substage in Ryazan
province, were published by Neumayr (1876) and Teisseyre (1884).
According to Zonov (1937, p. 35) Erymnoceras spp. occur in the lower part
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