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line of junction into an ochreous, reddish and yellow clay, which 
contains veins of fibrous gypsum, selenite, salt, and, it is said, ba- 
rytes. 
: Both the sandstone and limestone abound in caverns, ‘* the resort 
of the hyenas that nightly prowl among the burial-grounds without 
the walls of Cairo. One of these dens, into which” Mr. Newbold 
descended, ‘ contained the recent dung of the animal intermingled 
with human and other bones.” 
The valley which intervenes between Gebel Ahmar and the “Fossil 
Forest ” is excavated in the sandstone, the subjacent limestone being 
in some places exposed. 
The following inferences are drawn by Mr. Newbold from the 
phzenomena presented by the deposit of petrified trees :— 
(1.) He is of opinion that this part of Egypt has twice formed 
the bed of the ocean, and been twice elevated above the surface of 
the water. 
(2.) That the fossil trees lived between these epochs, when they 
were submerged or drifted into the ocean, and were covered up by a 
bed of rolled pebbles or sand; and that they were afterwards raised 
to their present position. 
(3.) That the elevation of the strata was effected gently and gra- 
dually, as the horizontal position is maintained. 
(4.) The retiring water is supposed to have removed the looser 
portions of the once continuous strata, and to have dispersed them 
with fragments of the fossil trees over the surface of the Egyptian 
and Libyan deserts, constituting the present accumulations of gravel 
and saline sands. 
(5.) From the little-worn aspect of the trunks, as well as the ans 
gularity and “nice adaptation ”’ of many of the fractured portions 
near Cairo, it is inferred, that, in that locality at least, the specimens 
rest at no great distance from the spot on which they were silicified ; 
and from the vertical position of a few of the trunks, that they pro- 
bably occur where they grew ; but until the vertical stems are traced 
down to roots fixed in a given stratum or at certain levels, marking, 
as in the Portland “ dirt-bed,’’ the ancient surface of dry land, Mr. 
Newbold hesitates to admit the hypothesis that the Cairo fossil de- © 
posit is the site of a submerged forest. 
Reposing horizontally, and at the height of 300 feet, on the in- 
clined limestone of the Gebel Ataka range which skirts the shore of 
the Red Sea below Suez, is a calcareous conglomerate, which Mr, 
Newbold thinks may represent the sandstone formation, as it rests 
on the marine limestone, and contains similar pebbles ; but it contains 
no silicified wood, nor any other fossils, except such as have been 
derived from the subjacent limestone. 
6. Post-Pliocene Deposits.—Around the head of the Gulf of Suez, 
as well as between the Red Seaand the cliffs which skirt its western 
shore, is an interrupted fringe rising in some parts to a height of 60 
feet, with an extreme breadth of four or five miles, composed of cal- 
careous deposits containing the remains of testacea, radiaria and 
corals, which now inhabit the Red Sea. Kossier and several other 
