Arkell.1956.Jurassic..

BRITISH SOMALILAND 309
at the top. Between 88 m. and 100 m. from base: Anavirgatites aff.
ambiguus (Schneid), A. cf. subambiguus Spath, 'Pseudovirgatites' cf.
silvescens (Schneid), Sublithacoceras cf. senex (Oppel), Simoceras sp.
nov.? [Presumably from this limestone came the Anavirgatites sp. nov.
figured by Stefanini, 1925, pi. xxviii, fig. 2, and Pseudinvoluticeras somalicum
Spath, 1925, p. 141, pi. xv, fig. 7.]
MIDDLE AND LOWER KIMERIDGIAN
Daghani Shales, 370 m. Olive gypseous shales with thin bands of
brown marl and limestone and bands of concretions (250 m.); resting on
grey calcareous mudstones and marls (120 m. or more). At 76-96 m. down,
belemnites and aptychi; at 111-151 m. down, Streblites aff. serratus
Burckhardt, Subdichotomoceras cf. simoceroides (Pavlow), Torquatisphinctes
aff. similis Spath, Idoceras sp., Hybonoticeras sp.; at 170 m. down, Idoceras
aff. balderum (Oppel), /. aff. laxevolutum (Fontannes) Burckhardt, Sutneria
aff. cyclodorsata (Moesch) Burckhardt, Aspidoceras (Orthaspidoceras) sp.,
Aptychus lotus (Park.); at 200 m. down, Orthaspidoceras aff. orthocera
(d'Orb.), Perisphinctids indet., Aptychus latus (Park.); at 260-310 m.
down, aptychi and belemnites. Posidonia somaliensis Cox, etc.
Wanderer Limestone, 103 m. Grey thinly-bedded lithographic limestone.
The Lower Kimeridgian age of this formation is proved by the
occurrence of Glochiceras nimbatum (Oppel) and Sutneria sp. There also
occur a number of Perisphinctids which Dr Spath determined before
recent nomenclatural and systematic revision of this difficult group.
From his names it appears to be an assemblage of Lower Kimeridgian
Discosphinctes, Virgataxioceras and other early Ataxioceratids, though
some of the names (perhaps requiring revision) suggest the Bimammatum
Zone. Zeilleria latifrons (Krumbeck), a brachiopod of the Syrian Glandarienkalk
(Kimeridgian) also occurs.
UPPER OXFORDIAN ?
Gahodleh Shales, 113 m. Olive to grey gypseous shales with Belemnopsis
tanganensis (Futterer) and B. aff. orientalis (Waagen), no ammonites.
Somalirhynchia africana Weir.
LOWER OXFORDIAN ? CALLOVIAN (pars)?
Bihen Limestone (upper part), 30 m. (or more). Dark grey massive
coral limestone. No cephalopods. Somalirhynchia africana Weir,
Terebratula cf. subsella Leymerie. A specimen of Pachyceras indicum
Spath, not in situ, possibly from this formation. The corals are all Upper
Jurassic kinds.
BATHONIAN
Bihen Limestone, lower part, 50 m. (or less). Thin-bedded grey and
brown rather shaly echinoid limestones, with thin bands of coral limestone
composed of similar corals, down to 17 m. from the base. Paracenoceras
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