Arkell.1956.Jurassic..

LOWER SAXONY I4I
Clydoniceras discus (Sow.) and Bullatimorphites bullatus (d'Orb.) were
found at the bottom (Kumm, 1952, p. 466).
The so-called Cornbrash is a limestone or sandy limestone facies,
in places including oolites, and reaching over 50 m. in thickness, which can
seldom be dated accurately but represents the whole (or in places parts)
of the Bathonian. In some exposures Clydoniceras discus and Oppelia
cf. aspidoides are recorded from it (Kumm, 1952, p. 465) indicating Upper
Bathonian; in others Parkinsonia wiirttembergica and many other fossils
of the Lower Bathonian. It also contains the only (slender) evidence of
Middle Bathonian in NW. Germany, namely records of 'Cadoceras
sublaeve' (Schott, 1932, p. 8), which in the Bathonian in other parts of
Europe have proved to be Tulites spp.
LOWER BATHONIAN (30 m.)
The Wiirttembergicus Beds, clays and shales with nodules, up to 30 m.
thick, are celebrated for fossils at Bielefeld clay-pits and formerly in a
railway-cutting at Eimen, near Hanover; also called Walkererde (Fuller's
Earth) and Ostrea knorri Beds (von Seebach, 1864, p. 39; Schloenbach,
1865; Steinmann, 1880; Wetzel, 1909, 1911, 1924, 1950; Kumm, 1952).
The principal ammonites are Parkinsonia (Oraniceras) wiirttembergica
(Oppel) (for which the preoccupied and invalid name compressus Quenst.
has been revived lately) and its compressed, involute allies, for which new
names have been introduced by Wetzel, 1950. Other important forms are
Parkinsonia (Gonolkites) postera (Seebach), P. (G.) convergens Buckman
(Schloenbach, 1865, pi. xxviii, fig. 3), P. (G.) fretensis Wetzel, P. (P.)
eimensis Wermbter sp., 1891 (type Schloenbach, 1865, pi. xxix, fig. 1),
Procerites schloenbachi de Grossouvre (type Schloenbach, 1865, pi. xxx,
fig. 1), Morphoceras sp. (Schloenbach, pi. xxix, fig. 5), Ebrayiceras sulcatum
Zieten sp. (Schloenbach, pi. xxviii, fig. 5), Lissoceras psilodiscus (Schloenbach),
L. inflatum Wetzel, and a number of species of Oppelia and
Oxycerites (Schloenbach, 1865, pi. xxx; Wetzel, 1950, pi. ix, with
many new names). The conclusion of Wetzel (1924, pp. 159, 163) that
these beds represent the Zigzag Zone has been confirmed by the finding
of Parkinsonia wiirttembergica and its allies in the Zigzag Zone in Lorraine,
Sicily, and North Africa.
UPPER BAJOCIAN (up to 100 m.)
In famous exposures at Bielefeld the Upper Bajocian is entirely developed
as clays and shales with layers of nodules. Owing to the numerous
ammonites and unusual thickness this is perhaps the most important
sequence of its age in the world (Wetzel, 1909, 1911, 1924, 1953; Althoff,
1928; Bentz, 1924, 1928; Kumm, 1952). The following is a summary
of the sequence:
Zone of Parkinsonia parkinsoni. Upper Parkinsonia Bed (Wetzel,
1911, p. 144) (Middle Parkinsonia Beds of Kumm, 1952, p. 430), with
P. parkinsoni Sow. sp. (syn. P. pseudoparkinsoni Wetzel), P. arietis Wetze
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