Arkell.1956.Jurassic..

KENYA (MOMBASA AREA) 321
Kimeridgian already familiar in Abyssinia and Somaliland. In addition
there are some ammonites of the Lower Oxfordian and a strong fauna of
Middle-Upper Callovian date, but no Jurassic assemblage later than
Middle Kimeridgian.
The greatest interest of the Mombasa Jurassics attaches, however, to
earlier Bathonian and Bajocian assemblages, here met with for the first
time in going southwards. These faunas consist largely of Phylloceratidae
and Lytoceratidae, families of the open ocean. We have evidently here
passed out of the Trans-Erythraean trough and into a broader sea which
extended to Cutch and connected round the east side of the Arabo-Somali
island with the Tethys of Persia and the Caucasus. The Bathonian
ammonites, being largely Phylloceratidae, fail to give an exact indication
of age relative to the neritic standard succession in NW. Europe, but it is
probable that they are older than the Upper Bathonian shallow-water
deposits of the Trans-Erythraean trough, Maghara and Palestine. The
Eligmus-Gryphaea costellata fauna of pelecypods is not found in Kenya,
but this could be due to facies difference. Nor can the Mombasa Bathonian
be compared to the ammonite-bearing Bathonian of central Arabia,
for Phylloceratidae and Lytoceratidae, so far as known, did not penetrate
into the Tuwaiq bay.
From the Callovian to the Middle Kimeridgian, as elsewhere, there is
much less local differentiation of facies, and both the Mombasa coast
and the Trans-Erythraean trough were in free communication with both
Cutch and Europe.
The following synopsis of the Jurassic column is based mainly on the
works of Dacque (1910, 1914) and Spath (1920, 1930, 1933—Cutch pt. 6).
Now that many ammonites have been figured and their chronological
significance has been pointed out, a great deal remains to be done by zonal
collecting to establish the detailed succession and to relate the individual
assemblages more closely to the local stratigraphy. At present the records
are to some extent conflicting: for instance, although the Changamwe
Shale contains both Kimeridgian and Upper Oxfordian faunas, it is said
to overlie Coroa Mombasa and other limestones which in part also contain
Kimeridgian forms. These anomalies will no doubt be resolved by local
workers in the future. Meanwhile the stratigraphical succession given
by McKinnon Wood (1930, p. 221), with revised stage-dating in the light
of Spath's 1.933 work and the present author's comments which follow,
is best placed here separate from the synopsis of the ammonite succession.
It is as follows:—
Changamwe Shale . . . . . Middle and Lower Kimeridgian and
Upper Oxfordian
Coroa Mombasa and other limestones and
shales
Rabai Shale .
Miritini Shale
Kibiongoni Beds
Kambe Limestone
Posidonia Shale
http://jurassic.ru/
Upper and Lower Oxfordian
Callovian
? Callovian
Bathonian (and Upper Bajocian ?)
Middle (and Upper ?) Bajocian
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