Arkell.1956.Jurassic..

478 BALTIC REGION AND POLAND
pi. viii, fig. 4). A noteworthy fossil in this zone is Trigonia hauchecornei
Schmidt, which is characteristic of the top of the Lower Volgian of
Pomerania.
'Niveau I, Couches A-F'. Zone of Zaraiskites scythicus. 20-25 m.
Grey micaceous clays, shales and marls, with some thin sandy beds.
Chiefly at two levels near base and at top are 55 species of fossils including
lumachelles of Oxytoma, also the vertebrates Ophthalmosaurus and
Cimoliosaurus, with Buchia pallasi Keys, and other spp., Zaraiskites
scythicus, Z. aff. quenstedti, Z. aff. pilicensis, Z. cf. tschernyschovi of Russian
authors, plus Z. sauvagei Lewinski. Clearly these beds correlate with
the Lower Volgian of both Pomerania and the Ural and Ilek Rivers, from
which latter similar ammonites are figured (see p. 494). Further, a
fragment of Z. scythicus figured by Lewinski (1923, pi. ix, fig. 4) is almost
identical with one figured from the Gorei Zone of Dorset by Buckman
(1926, Type Am. pi. DCLXXV); and Lewinski (pi. vii, fig. 9) figured
from the Alexandrae Subzone a fragment which he rightly likened to the
zonal index fossil, G. gorei (Salfeld).
The Scythicus Subzone has also been described about 20 km. south of
Tomaszow, with Buchia and some of the same ammonites (Passendorfer
1928).
KIMERIDGIAN (up to 370 m.)
In the neighbourhood of Tomaszow the junction of the Lower Volgian
with the underlying Kimeridgian is not exposed, and information from
borings is insufficient to establish the extent of the hiatus between the two
stages. No Hybonoticeras seems to have been recorded from Poland, but
Premik (1926, p. 374) believes on the evidence of some other ammonites
(not figured) that the Beckeri Zone is present in limestone facies at Biala.
The Pseudomutabilis Zone is probably represented by marls and clays
with lumachelles of Exogyra virgula and Gervillia which immediately
underlie transgressive Cretaceous sandstones in outcrops SW. of the
Lysa Gora and elsewhere; from them the only ammonite identified
seems to be Aspidoceras uhlandi (Oppel) (Siemiradzki, 1889, P- 53 > Swidzinski,
1931, p. 860).
It is to the Tenuilobatus Zone, however, that the bulk of the Polish
Kimeridgian belongs. Separation from the Upper Oxfordian is difficult,
owing to the great thickness and the paucity of ammonites. In the outcrops
SW. of the Lysa Gora Involuticeras sp., Aspidoceras cf. inflatum
(Quenst.) and Prorasenia stephanoides (Oppel) are recorded from the
highest 150 m., but below this there are a further 200 m. of limestones
without ammonites, assigned to the 'Astartien' (Swidzinski, 1931, p. 854)
on their gastropod fauna and on the occurrence of Septaliphoria pinguis
(Roemer) (Rozycki, 1948, p. 26). These beds are largely in coralline
facies or contain Diceras, but they comprise a wide variety of limestones.
The formation is thinner and the facies more favourable to ammonites
farther north. In marly limestones near Kalisz is an extensive ammonite
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