The other folds of Baharia, being parallel to the anticline just
dealt with, would at first sight appear to date from the same
movement. With regard to the syncline, however, two observations
appear which force us to consider its age as very much later; these
are, first, the occurrence of nummulites and other Eocene fossils
within the fold at a point 16 kilometres north of Ain el Haiss,
and secondly, the fact that at the northern extremity of the fold,
where it meets the eastern scarp, the Eocene beds are affected. With
regard to the first of these, the beds themselves, from which the
fossils had been derived, were not observed to be actually affected
by the fold, and therefore the evidence here, although suggestive,
is not conclusive. The evidence at the north end of the fold,
however, if substantiated, proves that the age of the fold must be
post-Eocene. With regard to the anticlinal fold on the north-western
plateau there is no question, as this clearly affects the Eocene
beds; it also is parallel to the other folds. These folds affecting
Eocene beds, lead us to the conclusion that there was another period
of possibly ever more important earth-movements, of the exact date of
which we cannot be certain, although it is not impossible that it was
closely connected with those great earth-movements of Pliocene times,
which gave rise to the chief topographic fixtures of N.E. Africa
and S.W. Asia.
[Sidenote: Summary.]
_Summary of the Geological History of the Oasis._—The oldest[61]
sedimentary deposit in Egypt is the Nubian Sandstone of the
Cretaceous. From the general absence of marine shells in this rock
we may premise that the deposit was laid down in an inland sea or
lake, which must have covered an enormous extent of country. In the
northern part of Egypt the upper part of the Nubian Sandstone becomes
fossiliferous, the fauna having an undoubted Cenomanian aspect; this
is the case in Wadi Araba, at Abu Roash and in Baharia. Further to
the south, however, as in Dakhla, the Nubian Sandstone first becomes
fossiliferous in Senonian times. We may explain this difference
in the two localities on the supposition that a gradual subsidence
was taking place with a corresponding gradual encroachment of the
sea from the north, which covered the northern part of the country
(including Wadi Araba, Abu Roash and Baharia) in Cenomanian times
but did not reach the latitude of Dakhla till considerably later,
i.e., in Senonian times.
From the Cenomanian onwards throughout the Cretaceous, the
Baharia area was one of continued subsidence, the lithological and
palæontological characters of the beds showing evidence of a gradual
increase in conditions of depth, until the maximum was reached in
the deposition of the White Chalk in Danian times.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account