NEWBOLD ON THE GEOLOGY OF EGYPT. 333 
presented to the Society by that gentleman from the vicinity of the 
petroleum deposits of Gebel Ezzeit, and also iron ore. It is not 
however clearly ascertained whether the specimens from Ezzeit be- 
long to the limestone under consideration, or to the more recent 
formation. Captain Moresby found a hill abounding in sulphur 
within the limestone limits near Myos Hormus. 
Organic Remains in the Limestone.—After a series of laborious 
researches, Ehrenberg* has concluded that the compact limestone 
rocks which bound the Nile in the whole of Upper Egypt (7. e. the 
lower beds of the limestone formation), and extend far into the Sa- 
hara, or desert, as well as the compact limestone rocks in the north 
of Arabia, are, in the mass, composed of the animalcules of the Eu- 
ropean chalk. The result of an examination of the chalk of Brighton 
and the limestone of Egypt showed that the principal microscopic 
forms in these rocks consist of 25 species of caleareous-shelled Poly- 
thalamia, 39 species of siliceous-shelled Infusoria, 7 species of soft- 
shelled Infusoria of the flints, and 5 species of siliceous plants. 
None of the forms of Polythalamia now living in the Red Sea are found 
among the animalcules of the chalk or limestone of Egypt and Ara- 
bia. It need hardly be observed, since the discoveries of Mr. Lons- 
dale, D’Orbigny and Tennant, that the existence of similar Poly- 
thalamia in the Egyptian rocks does not go to identify these beds in 
point of geological age with the European chalk. 
Ammonites are stated by Clot Bey to be found in the limestone 
near the Pyramid+. 
Lefevre{ states that Echinites identical with those of Matta have 
been found at Esneh ; and Hippurites, Placuna, Vulsella and fossil 
fish, near Cairo, to which may be added Nautili of large dimensions, 
corallines, crabs, fishes’ teeth and nummulites. There isa large bed of 
Ostrea carinata? between Kossier and Thebes. Mr. Nash§ found 
Cardia and a Turritella in the same locality, and states the flints in 
the limestone there to be all fossil sponges, Alcyoniz, &c. The so- 
called Egyptian jaspers and agates, which occasionally replace the 
chert, have been pronounced by Mr. J. Bowerbank|| to be destitute 
of spongeous remains. He ascertained that they consisted of small, 
irregular, light-coloured grains imbedded in a banded semi-transparent 
matrix of silica, in a state very much like that in which it exists in 
chalk flints and greensand cherts, and that they contained vast num- 
bers of Foraminifera, unequally distributed through the layers com- 
pesing the agate, closely resembling those found in chalk flints, and 
often difficult to distmguish from the species found in the Grignon 
sand of the Calcaire grossier. In many of the variegated Egyptian 
jaspers the organic siliceous elements are no longer to be distinctly 
found, a fact ascribed by Ehrenberg 4 to the circumstance of their 
* Lond., Edin. & Dub. Phil. Mag. vol. xviii. pp. 384, 389, 444. 
+ Apercu Générale de |’Egypte, vol. i. p. 144. 
¥ Bullet. Soc. Géol, de Paris, vol. x. pp. 144, 234. 
§ Edin. Phil. Journ. vol. xxii. pp. 45-47. 
|| Proc. Geot. Soc. of London, vol. iii. pp. 435, 436. 
{ Lond., Edin. & Dub. Phil. Mag. vol. xviii. pp. 395, 396. 
