NEWBOLD ON THE SILICIFIED WOOD OF EGYPT. 351 
of proper instruments prevented my giving a 
more regular survey of the locality and its vici- 
nity. 
With regard to Burckhardt’s theory of the 
modern origin of the petrifactions (since the time 
of Nechos, about 600 B.c.) and the process of 
silicification having been caused by the winter 
rains and torrents, I will content myself with ob- 
Serving that, in general, the largest and most 
perfect trunks are found on the sides and sum- 
mits of hills, or in other positions, elevated above 
the level of existing streams and inundations, 
where the presence of springs is rarely known, 
and often imbedded in solid rock, containing in 
some situations pelagic remains. 
The site of the petrifactions lies in the Suez 
desert about seven miles east by south from 
Cairo, between the usual caravan-track to Mecca, 
and the more southerly but less-frequented camel 
route that leads from the village immediately 
south of Old Cairo through the Valley of the 
Wanderings (Wadi et-Tih). The area over which 
they are scattered presents an irregular super- 
ficies, extending about three miles and a half 
southerly towards Wadi et-Tih, and about four | 
miles in an easterly direction. The whole of 
this plateau is considerably elevated above the 
level of the Nile even during the highest imun- 
dations, lying on the slope of the Mokattem 
range as it recedes easterly from the river, where 
it presents the bold and precipitous escarpments 
that form the eastern limits of the valley of the 
Nile. The belt of desert that is passed between 
the petrifactions and Cairo rises gradually, but 
irregularly, from the city walls, and presents an 
undulating surface, here and there broken by low 
and irregular elevations, and covered with a light- 
coloured, quartzy sand, mingled with rolled peb- 
bles of quartz, jasper, Egyptian pebble, silicified 
wood, chert, and fragments of crystallized sul- 
phate, and carbonate of lime and muriate of soda. 
Near the top of a broad shallow defile that 
leads up to the table-land skirting the site of the 
petrifactions, the fragments of silicified wood be- 
‘come more numerous, and their edges less worn. 
Another shorter but steeper ascent to the right 
being gained, the traveller stands upon the edge 
of the fossil forest—one dreary, arid expanse of 
sand, treeless and almost shrubless, rugged with 
West. 
Libyan range. 
Nile. 
c, @. Marine limestone of the Mokattem and Libyan ranges. 
d, Alluvium covering valley of the Nile. 
d, 
Mokattem. 
Fig. 7 
Section E. and W. showiny the site of the Fossil Forest. 
b. Sandstone and pudding-stone imbedding silicified trees. 
a, a. Sand and gravel covering surface of desert. 
Fossil Forest. 
b, 
f 
dark-coloured knolls, and intersected by a few dry raim-channels. 
East. 
