Arkell.1956.Jurassic..

MADAGASCAR 341
Lemoine and many other forms. The conspicuous Macrocephalitids
have long been known, especially through the photographs of Lemoine
(1910, pis. i-iv; since largely renamed). A list, together with identifications
of the associated ammonites of the genera Ptychophylloceras, Calliphylloceras,
Holcophylloceras, Lytoceras, some Hecticoceratids, Hubertoceras,
Choffatia and Indosphinctes, is given by Spath (1933, p. 821). The large
supporting fauna includes Eligmus rollandi Douville (Barrabe, 1929,
pp. 111-19; Basse, 1934, pp. 59-67). Besairie (1936, p. 62) attempted to
separate a third zone which he correlated with the Koenigi and Calloviense
Zones, but the assemblages he placed on this horizon belong in part to
the Macrocephalus Zone (the Maintirano faunule, which contains M.
aff. typicus Blake and Kheraiceras cosmopolita P. & B. sp.) and in part
seem to be the same as the Hecticoceratidae beds assigned to the Anceps
Zone. His plates vii and viii illustrate more of the Macrocephalitids and
other fossils from the Lower Callovian, including forms of Choffatia
as well as of Macrocephalitids that could hardly be distinguished from
those of the English Upper Cornbrash. (See also Besairie, 1930, pi. x.)
The Macrocephalitidae of SW. Madagascar have since been monographed
by Basse & Perrodon (1952), and Collignon (1953) has listed a number of
forms from the north of the island. A good representative collection of
15 species from near Sakahara was sent me in 1954, collected by Dr P. E.
Kent.
BATHONIAN
At least in some places in the north the Lower Callovian ammonite
limestones pass down by intercalation into shallow-water Bathonian
pelecypod beds with Corbula lyrata Sow., Protocardiagrandidieri (Newton),
Pseudotrapezium depressum Newton, and Astarte baroni Newton and,
locally, corals and at the base reefs of Girvanella. The Bathonian limestones
are very thick and form dry karst country like the 'causses' in France.
At the base in places are marls with dinosaur bones. The upper beds,
with Corbula, are transgressive in the south, overlapping on to Trias
(Barrabe, 1929, p. 107; Basse, 1934, p. 45 ff.). These Upper Bathonian
pelecypod beds (locally with Eligmus: see Besairie, 1930, pi. x, fig. 4)
were described and correctly dated to the Bathonian by H. Douville
(1904, p. 212); they are, however, Upper not Middle Bathonian as Besairie
states (1936, p. 120, with good figures of the pelecypods, pi. vii). By their
fossils, facies and transgressive quality they correspond to Upper Bathonian
beds in southern Tunisia, Egypt, Somaliland, ? Jubaland, Cutch (Kuar
Bet Beds, see p. 391) and Burma. Until recently the only Bathonian
ammonite known with certainty from Madagascar was a single small
Cadomites cf. rectelobatus (Hauer), found above the coral limestones in
the north (Besairie, 1930, p. 534, pi. vii, fig. 6). If a fragmentary 'Cardioceras'
figured by Barrabe (1929, p. vii, fig. 30) is a Clydoniceratid as Mme
Basse (1952, p. 86) surmises, this too probably came from the Bathonian
beds. East of Andranomantsy, in the north of the island, Collignon
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