Sn 
TRANSACTIONS OF SECLION E. 877 
Sometimes the drainage, instead of flooding open spaces and forming chotts, 
finds its way through the permeable sand till it meets impermeable strata below it, 
thus forming vast subterranean reservoirs where the artesian sound daily works as 
great miracles as did Moses’ rod of yore at Meribah. I have seen a column of water 
thrown up into the air equal to 1,500 cubic métres per diem; a quantity sufficient 
to redeem 1,800 acres of land from sterility and to irrigate 60,000 palm trees. This 
seems to be the true solution of the problem of an inland sea; a sea of verdure and 
fertility caused by the multiplication of artesian wells, which never fail to bring 
riches and prosperity in their train. 
The climate of the Sahara is quite different from that of what I have called the 
Mediterranean region, where periodical rains divide the year into two seasons. 
Here, in many places, years elapse without a single shower ; there is no refreshing 
dew at night, and the winds are robbed of their moisture by the immense conti- 
nental extents over which they blow. There can be no doubt that it is to these 
meteorological, and not to geological, causes that the Sahara owes its existence. 
Reclus divides the Mediterranean into two basins, which, in memory of their 
history, he calls the Phoenician and the Carthaginian, or the Greek and Roman 
seas, more generally known to us as the Eastern and Western Basins, separated by 
the island of Sicily. 
If we examine the submarine map of the Mediterranean, we see that it must 
at one time have consisted of two enclosed or inland basins, like the Dead Sea. 
The western one is separated from the Atlantic by the Straits of Gibraltar, a 
shallow ridge, the deepest part of which is at its eastern extremity, averaging 
about 300 fathoms; while on the west, bounded by a-line from Cape Spartel to 
Trafalgar, it varies from 50 to 200 fathoms. Fifty miles to the west of the Straits 
the bottom suddenly sinks down to the depths of the Atlantic, while to the east it 
descends to the general level of the Mediterranean, from one to two thousand 
fathoms. 
The Western is separated from the Eastern Basin by the isthmus which extends 
between Cape Bon in Tunisia and Sicily, known as the ‘ Adventure Bank,’ on which 
there is not more than from 30 to 250 fathoms. The depth between Italy and 
Sicily is insignificant, and Malta is a continuation of the latter, being only separated 
from it by a shallow patch of from 50 to 100 fathoms; while to the east and west 
of this bank the depth of the sea is very great. These shallows cut off the two 
basins from all but superficial communication. 
The configuration of the bottom shows that the whole of this strait was at one 
time continuous land, affording free communication for land animals between 
Africa and Europe. The paleeontological evidence of this is quite conclusive. In 
the caves and fissures of Malta, amongst river detritus, ave found three species of 
fossil elephants, a hippopotamus, a gigantic dormouse, and other animals which 
could never have lived in so small an island. In Sicily, remains of the existing 
elephant have been found, as well as the Elephas antiquus, and two species of 
hippopotamus, while nearly all these and many other animals of African type have 
been found in the pliocene deposits and caverns of the Atlantic region. 
The rapidity with which such a transformation might have occurred can be 
judged by the well-lmown instance of Graham’s Shoal, between Sicily and the 
island of Pantellaria; this, owing to volcanic agency, actually rose above the 
_ water in 1832, and for a few weeks had an area of 3,240 feet in circumference and 
a height of 107 feet. 
The submersion of this isthmus no doubt occurred when the waters of the 
Atlantic were introduced through the Straits of Gibraltar. The rainfall over the 
entire area of the Mediterranean is certainly not more than 80 inches, while the 
eyaporation is at least twice as great; therefore, were the Straits to be once more 
closed, and were there no other agency for making good this deficiency, the level 
of the Mediterranean would sink again till its basin became restricted to an area no 
_ larger than might be necessary to equalise the amount of evaporation and precipita- 
tion. Thus not only would the strait between Sicily and Africa be again laid dry, 
but the Adriatic and Aigean Seas also, and a great part of the Western Basin. 
The entire area of the Mediterranean and Black Seas has been estimated at 
. 
