Arkell.1956.Jurassic..

THE MIDDLE EAST 287
Cretaceous. Andrew restricted his remarks to the area east of the Nile,
but there is no reason to doubt that they hold also for the much greater
area of Libyan Desert to the west and south.
Accordingly, over this north-east corner also of the vast African shield,
it can be concluded that either Jurassic seas never extended, or all their
sediments were denuded before the Upper Cretaceous. The most
probable conclusion is that the area was for the most part dry land
undergoing peneplanation in the Jurassic; that the various Jurassic
transgressions temporarily carried shallow seas over the fringes of the
landmass, but that these thin marginal deposits were destroyed or
trimmed back by Lower Cretaceous denudation before deposition of the
Nubian Sandstone.
COASTS OF THE GULF OF SUEZ, CENTRAL SINAI AND NILE DELTA
On the west side of the Gulf of Suez the Eocene limestone tableland,
where it reaches its highest elevations of 1000 to 1500 metres in the North
and South Galala Plateaux, is cut through almost to sea-level by the great
erosion hollow of Wadi Araba, 50 miles long and 20 miles wide. The
floor of the hollow consists of Carboniferous sandstones with thin sandy
and sometimes crinoidal limestones crowded with the brachiopods
Spirifer and Dielasma. Along both the north and south sides of the
wadi, unfossiliferous Nubian Sandstone of Cretaceous type has been
observed at a number of places to rest directly on the Carboniferous,
with only slight unconformity (Arkell, 1951). After the scarp turns NE.,
along the faulted coast of the Gulf of Suez, however, a wedge of Jurassic
rocks comes in and thickens rapidly. The first known good exposures
are close to the coast road on the south side of Ras el Abd (29°33'3o"N.,
32°2i'3o"E.) (pi. 13). The rocks consist of over 100 m. of marine marls,
limestones and sandstones with Bathonian pelecypods and brachiopods
(Farag, 1948). A few kilometres farther north, at the NE. corner of the
North Galala Plateau, in a fault block under Khashm el Galala, the
Bathonian strata are about 170 m. thick (pis. 13, 14).
At the base of the section at Khashm el Galala are about 50 m. of
unfossiliferous sandstones of presumed Triassic age. Resting upon an
irregular surface of the sandstones are some thin bands of pink sandy
and shaly marls which have yielded a flora of Rhaetic-Infra Liassic age,
including Equisetites, Pklebopteris, Zamites and ? Cladophlebis, identical
with remains found in the Kohlan Sandstones of the Yemen (Carpentier &
Farag, 1948). Immediately above the plant beds follow the marine
Bathonian beds, a long series of marls and thin limestones, sandy limestones
and sandstones, with at least 20 species of pelecypods, brachiopods
and (more rarely) gastropods (Sadek, 1926, p. 35). Shells such as Trigonia
cf. pullus Sowerby, Gervillia waltoni, Astarte, Nucula, etc. occur in profusion
in certain thin ferruginous bands, the tests preserved intact. Other
slabby limestones are crowded with crushed Rhynchonellids and resemble
http://jurassic.ru/