Arkell.1956.Jurassic..

264 NORTH AFRICA
dominant ammonites of this fauna are Ermoceras deserti Douville and
E. runcinatum Arkell, here found 3300 km. west of the nearest known
occurrence, in Sinai. In the same beds occur Cadomites aff. deslongchampsi
(d'Orb.), C. cf. daubenyi (Gemm.), C. cf. septicostatus Buck.,
Stephanoceras humphriesiforme (Roche), Leptosphinctes cf. leptus Buck.,
Cleistosphinctes cleistus (Buck.) and Oppelia subradiata (Sow.). This
fauna occurs at the top of 4-5 m. of limestone which represents a condensed
Bajocian, for it is underlain by the Toarcian. Above it follow at least
1000 m. of marls and argillaceous limestones with Posidonia, all of which
must belong to the Upper Bajocian, since it underlies the Lower Bathonian
fauna of El-Harchaia with Oraniceras, described by Flamand (see next
section). (Arkell & Lucas, 1953.)
MIDDLE BAJOCIAN
The Sowerbyi, Sauzei and Humphriesianum Zones all seem to be
represented (the 1st, 2nd and 3rd Bajocian zones of Termier, 1936,
p. 894), judging by the records and the few figures published by Gardet
& Gerard (1946). From the High Atlas of Midelt and near Figuig are
recorded numerous Witchelliae and Sonniniae, Zurcheria, Emileia brocchi
(Sow.), Otoites sauzei (d'Orb.), Skirroceras bayleanum (Oppel), Phylloceras
and Lytoceras (Dubar, 1934, p. 85; Verlet & Roch, 1940), and from
the Middle Atlas the same plus Chondroceras, Stephanoceras, Hyperlioceras
and Dorsetensia (Termier, 1936, pp. 1343-51), and beds with Stephanoceras
humphriesianum (Sow.) and other species (Colo, 1951, p. 89). Forms
figured by Gardet & Gerard are Poecilomorphus cf. angulinus Buckman
(pi. iii, fig. 11), Emileia cf. brocchi (Sow.) (pi. iii, fig. 15), Stephanoceras
psilacanthus Wermbter (pi. iii, fig. 24, not humphriesianum), S. cf. rhytus
(Buckman) (pi. viii, fig. 1), and Skirroceras cf. bayleanum (Oppel) (pi. viii,
fig. 2). These beds are transgressive, overlapping locally on to Middle
and Lower Lias (Termier, 1936, p. 885; Dubar, 1938). In the eastern
High Atlas they pass into the Boulemane Marls (Choubert, 1938, see
below), and in the northern Middle Atlas the Humphriesianum Zone
overlies thick Sauzei and Sowerbyi Zones developed as marly limestones
(Colo, 1951).
LOWER BAJOCIAN
The Opalinum, Scissum and Murchisonae Zones are represented by
a number of ammonites (Termier, 1936, pp. 1317-20; Choubert, 1937;
Verlet & Roch, 1940, pp. 78-9; Colo, 1951): Leioceras cf. opalinum,
Haplopleuroceras subspinatum Buckman, Hammatoceras spp., Ludwigia
spp., Erycites spp. (Termier, 1936, pi. xxiii, fig. 12; Gardet & Gerard,
1946, pi. iii, fig. 10) and Tmetoceras cf. hollandae Buckman (Termier,
1936, p. 1318, non Gardet & Gerard, which is not a Tmetoceras). The
whole of the Bajocian passes laterally into the Boulemane Marls, which
persist for hundreds of miles to the Algerian border and are said to attain
1200 m. in thickness in the Talsint trough in the eastern High Atlas
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