DELTA OF THE NILE. 
163 
the sea once washed the base of the rocks on which 
the Pyramids of Memphis stand; the present base 
of which is washed by the inundation of the Nile, 
at an elevation of seventy or eighty feet above the 
Mediterranean. 
The Nile once entered the sea by seven principal 
mouths, two of which are now entirely blocked up 
by sand, and have disappeared. The city of Foah, 
which in the fifteenth century stood on one of 
these branches, is now more than a mile inland, 
and Pharos, anciently an island, which Homer says 
was one day's voyage by sea from Egypt, is now a 
portion of the continent.* An analysis of the mud 
of the Nile gives, according to Girard, one half of 
argillaceous earth, and about one fourth of carbon- 
ate of lime, nearly one tenth of carbon, the re- 
mainder consisting of water, silex, oxide of iron, 
and carbonate of magnesia. At a small distance 
from the shore of the delta, the depth of the Med- 
iterranean is about twelve fathoms ; it then gradu- 
ally increases to fifiy, and then suddenly descends 
to three hundred and eighty fathoms, which is sup- 
posed to be nearly the original depth of the sea. 
Deltas of the Ocean. — These are variously modi- 
fied by the influence of tides and currents, which 
prevail to a greater or less extent in every ocean, 
as they often distribute the transported sediment to 
distant or, perhaps, unknown places of deposite. 
Delta of the Ganges, — The area of this delta is 
considerably more than double that of the Nile, and 
its head commences at least 220 miles in a di- 
rect line from the sea. Its base is 200 miles long, 
and it is bounded on either side by an arm of the 
Ganges. Near the sea it is intersected by a laby- 
rinth of rivers and creeks, generally filled with salt 
water, and forms a wilderness inhabited by tigers 
and alligators. The Ganges pours such a quantity 
* Odys., book iv., V. 355. 
