- 
NEWBOLD ON THE GEOLOGY OF EGYPT. 345 
yond their reach, and from the inhabitants of the valley of Egypt 
having been obliged from time to time to raise their towns. They 
omitted however to raise their ancient nilometers correspondingly 
with the rising level of the alluvium at their base; hence the greater 
apparent height marked upon them by the inundation at present than 
formerly. 
During the lapse of ages, the natural consequence of this slow 
heightening of level, in the lower parts of Egypt, will be to throw 
a greater depth of water into the upper parts of the river, which 
may in turn become so much elevated above the low parts of the 
Libyan desert as to force the stream to seek a new channel, probably 
by the low levels of the Fuioom and Bahr bila Maieh valleys, to the 
Mediterranean, in the vicinity of the Mareotis lake, imparting a new 
physical aspect to the sterile wastes of Lower Egypt. 
A tendency of the river at certaim points to shift its bed easterly, 
towards the basis of the Arabian cliffs, will retard the probable effects 
of the raising of its bed just contemplated. 
On the east bank many of the interesting monuments of Koum 
Ombos have been swept away, and the rest appear to await a similar 
fate*. Farther down, on the same bank, the ancient stone and brick 
quay at Luxor, and the temple itself, are in great danger. The in- 
teresting ruins of Gou-el-Kebir have disappeared, partly from the 
encroachments of the river, and partly from the depredations of the 
natives. An old inhabitant of the present village pointed out to me, 
from the summit of the high mud-cliff now overlooking this part of 
the river, its former traditional channel, nearly a mile to the west- 
ward. This tendency in the bed of the river to shift easterly arises 
principally from the lower comparative level of the surface at the base 
of the Arabian cliffs, which are of a more precipitous and continuous 
character than those on the Libyan bank. The strong prevalent 
west and north-westerly winds not only exert a direct influence in 
throwing the mass of water m an east and south-east direction, but 
also continually force upon its western bank the drifted sands of the 
desert. 
Some change of the bed is effected every inundation, by the al- 
teration the latter causes in the mud-banks of the preceding year ; 
high projecting cliffs of which, hardened and cracked by the sun, are 
often loosened and toppled down into the eddying waters of the 
rising stream with great noise, their component parts again to be held 
in watery suspension, and distributed over the surface of the soil. 
When passing down the Nile in July, our boat narrowly escaped 
being swamped by the swell succeeding the fall of one of these mud- 
slips. 
Delta of the Nile.— From the physical conformation of the country 
between Cairo and the Mediterranean, including the delta and its 
marine basis, it is evident that it once formed an inland bay, which 
Herodotus} supposed to have been filled by the Nile with mud, and 
_thus raised above the sea. It is clear, however, from the absence of 
‘any marine remains (except such as have been derived from the sub- 
* Vyse, vol. i. p. 65. + Euterpe, 10 & 11. 
