516 Are We Drying Up? [September, 1 
shrinking in the area of Lake Aral is that the evaporation from 
its surface is in excess of the supply received by it from the 
Amu and from the Syr.” 
: Similar facts in regard to the diminished quantity of water in 
Arabia are cited by various travelers in that country. Some of 
them are given in Mr. Marsh’s volume, to which reference has 
already been made. 
In Africa the existence of extensive ruins in the Great Libyan 
Desert, in a region quite destitute of water, and which is now 
entirely uninhabited, may be taken as a strong indication of 
great changes since the historic period. Dr. Livingstone, in his 
travels in southern Central Africa, was again and again much 
impressed with the proofs presented to him of a rapid and exten- 
sive diminution within recent times of the amount of water in 
the lakes and rivers of that region.! 
But it is not only in the Old World but also within our own 
territory that a former much greater extension of the water sys- 
tem can be easily demonstrated. ‘The terraced character of the 
rivers of our northeastern States afford ample proof that these 
once conveyed a much larger quantity of water than they now 
do. The facts have been set forth in detail by various geological 
writers, and especially in President Hitchcock’s Surface Geology: 
It is true that geologists have only lately generally admitted the 
apparently self-evident fact that the origin of these terraces 18 
due to a diminution in the quantity of water which the streams 
have conveyed, and not to any sinking or rising of the land. 
It is, however, in the region west of the Rocky Mountains, €$- 
pecially in the “ Great Basin,” that we find a condition of things 
most strikingly resembling that already noticed as existing a 
rea occupied by — 
Central Asia. Everywhere, throughout the a — 
Utah and Nevada and portions at least of the adjacent territories 
the evidences of desiccation within the most recent geolog! 
iki ht 
period are very striking. These facts were first brought | 
volume i. (1865), 
notice in part in the Geology of California, 
which the terraces surrounding Mono Lake were 
the former greater extension of this and the adjacent l — 
to be beyond doubt. The same thing was also noticed and n 
mented on in the Yosemite Book (1869). The terraces a 
rounding Great Salt Lake are so conspicuous that no trav - 
1 See Livingstone’s Missionary Travels in South Africa. London. 1857. Page St 
He says: “All the African lakes hitherto discovered are} shallow 1m consequeh” 
: : $ ia 
their being the mere residua of very much larger ancient bodies of water. 
described, 
akes show? 
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