336 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
Economical Uses of the Sandstone.—The rock in the vicinity of 
Cairo has been quarried for ages past for grindstones. The more 
compact varieties have been lately employed by the Pacha for mac- 
adamizing the open squares of his palaces. 
Caleareous Conglomerate.—Previous to passing to the tertiary 
beds on the shores of Egypt, I shall briefly mention a calcareous con- 
glomerate which I found reposing horizontally on the inclmed lime- 
stone of the Gebel Ataka range, skirting the shore of the Red Sea 
below Suez, at about 300 feet above the level of the sea. From the 
similarity of its imbedded pebbles, and position on the limestone, it 
may be probably referred to the overlying sandstone formation just 
described, though no silicified wood, nor pelagic remains, except such 
as had been derived from the subjacent limestone, were seen in it. 
Post-Pleiocene: Extent and Position.—Around the head of the 
Gulf of Suez, and between the Red Sea and the cliffs that skirt its 
western shore, runs a fringe of elevated coast-land, rismg im some 
localities to the height of sixty feet from the level of the ocean, and 
from four to five miles in extreme breadth. At a few poimts, however, 
the fringe is interrupted by the cliffs sweeping down to the water’s 
edge. This coast has for its basis calcareous and gypseous marls, a 
loose calcareous sandstone and a coralline limestone, abounding with 
fossil shells, Echinidee, Asterias, spines of Cidaris—all of recent species ~ 
according to Mr. Lyell*, and agreeing in every instance with those now 
living in the Red Sea. Several towns, among others Kossier, stand 
on this coral reef, which, it is evident, must have been elevated sub- 
sequent to the Pleiocene period. It is more than suspected, from the 
obliteration and shallowing of harbours, known to have been deep 
in ancient times, that this elevating process is still in slow though 
gradual operation. It is worthy of remark, that though traces of 
volcanic agency are visible in the sulphuriferous rocks of Ezzeit, its 
petroleum wells, the hot springs of Hummam Feraon, and Tor on 
the opposite coast, the still active volcano of Gebel Teer, and the 
lavas of Aden, earthquakes are almost unknown in the history of 
Egypt ;—I say almost, because it has been asserted that the vocal 
statue of Memnon was thrown down and broken by the shock of an 
earthquake. 
The question however naturally occurs to the traveller, on 1 casting 
his eyes on the unbroken form of its brother colossus only a few 
paces distant, why did not this statue share a similar fate? From 
the erect position of the pyramids, obelisks, and temples of ancient 
Egypt, and the little disturbance visible in the uplifted beds, it may 
be inferred that the forces which effected the upheaval of the shores 
of the Red Sea were exerted in a gentle and gradual manner. Many 
have supposed that the Isthmus of Suez, now dividing the Medi- 
terranean and Red Seas, has been recently formed either by a process 
of submarine elevation, or by drift; but the great difference existin 
in the group of fishes, testacea and zoophytes inhabiting the two 
seas, though only fioeant seventy miles, militates strongly against 
such a theory. Ehrenbergt states that it appears Bus that 
* Principles, vol. iv. pp. 39, 40, 4th edition. 
+ Lond., Edin. and Dub. Phil. Journ., vol. xviii. pp. 380, 444. 
