Arkell.1956.Jurassic..

268 NORTH AFRICA
TITHONIAN
Red and white shaly marls with interbedded hard limestones have yielded
Ptychophylloceras ptychoicum and other spp., Sowerbyceras loryi Munier-
Chalmas, Haploceras caractheis (Zeusch.), Berriasella callisto, Spiticeras
cf. pseudogroteanum Djanelidze, aptychi and Pygope janitor Pict.
KIMERIDGIAN
Evidence for this stage is inconclusive. Lacoste (1934, pp. 178-80)
assigns several ammonites to the Lower Kimeridgian, of which Phylloceras
cf. canavarii Menegh., Simoceras parateres Canavari, Nebrodites doublieri
(d'Orb.) and Taramelliceras trachynotum (Oppel) alone may be
Kimeridgian.
UPPER OXFORDIAN
To this substage belong Sowerbyceras tortisulcatum (d'Orb.) and some
Perisphinctids (Lacoste, 1934, pp. 178-80).
LOWER OXFORDIAN AND CALLOVIAN have yet to be found, but Lacoste
believes the succession to be continuous. The presence of Callovian
not many miles away, in the misnamed 'Eastern Rif (Marcais, 1931),
suggests that he may be right.
LOWER BATHONIAN
At Jebel Arechko, in red marly limestones like the Bajocian, Lacoste
(1934, p. 176) obtained Morphoceras aff. multiforme (= polymorphum
d'Orb.), Ebrayiceras cf. pseudoanceps (Ebray) and Cadomites or Polyplectites.
MIDDLE BAJOCIAN
At Zerhoun in the Pre-Rif (north of Meknes and west of Fez) and at
Mjara in the Southern Rif, a rich Bajocian fauna has been found. At
Mjara the facies is red marls and marly limestones; at Zerhoun it is in the.
form of thick sandstones, oolites, freestones, dolomites and marls, changing
rapidly and reminiscent of the English Inferior Oolite of the Cotswolds
(Lacoste, 1934, p. 176, Gubler, 1938). The only Upper Bajocian ammonite
recorded is Strigoceras truellei (d'Orb.), but as this was found associated
with many Middle Bajocian ammonites, it was probably one of the earlier
species of Strigoceras. The other ammonites are Stephanoceras humphriesianum
(Sow.), S. plicatissimum (Quenst.), Skirroceras freycinati (Bayle),
Normannites braikenridgei (Sow.) [? orbignyi Buckman], Otoites contractus
(Sow.), Sphaeroceras brongniarti (Sow.), Dorsetensia subtecta (Buck.),
Poecilomorphus cycloides (d'Orb.). At Mjara in the Southern Rif Holcophylloceras
mediterraneum and its allies are common. In addition to these,
some Sonninids of the Sowerbyi Zone are said to occur intimately mixed
in the fauna of the Lower Bajocian in the Pre-Rif (Gubler, 1938, pp.
137-8); they are Sonninia propinquans Bayle (the type species of the genus),
S. deltafalcata (Quenst.), Witchellia sayni Haug (corrugata Douv. non
Sow.), and W. crassifalcata Dorn.
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