652 THE FRESH-WATER LOCHS OF SCOTLAND 
braces the whole floor of the ocean beyond 200 miles from continental 
shores and deeper than 1400 fathoms — the mean sphere level. It 
covers 98,000,000 of square English miles, or 69J per cent, of the 
water-surface and 50 per cent, of the entire surface of the globe. 
Sunlight never penetrates to this area. The temperature is not far 
removed from 0"" C. (32° Fahr.), and evidences of erosion or transport 
are absent. The deposits consist of red clays and organic oozes, 
and particles of quartz sand are extremely rare or wholly absent 
(except in those regions affected in recent times by floating ice). 
The rate of deposition is very slow, and is at a minimum towards the 
central parts of the great ocean basins, where the depths are from 
3000 to 5000 fathoms, and sharks' teeth, ear-bones of whales, man- 
ganese nodules, zeolitic minerals, and cosmic spherules are found in 
relatively great abundance. Deposits similar to those now forming in 
this abysmal area have not yet been traced in the geological series of 
rocks exhibited for examination on the continental areas. We may say 
that on one-half of the earth's surface there are now being laid down 
formations which are not similar to any found in the geological series. 
TABLE I 
Principal Lakes of the World arranged according 
TO Superficial Area 
Area in 
Area in 
Name of Lake. 
Square 
Miles. 
Name of Lake. 
Square 
Miles. 
Caspian * . . . . 
180,000 
Eyre* 
3,200 
Superior .... 
31,200 
Athabasca .... 
3,000 
Victoria Nyaiiza . 
26,200 
Reindeer .... 
2,490 
Aral* 
24,400 
Issik-kul * . ... 
2,300 
Huron (with Georgian Bay) . 
23,800 
Vener ..... 
2,149 
Michigan .... 
22,450 
Winnipegosis 
2,080 
Chad 
/ 20,000 
{ to 7,700 
Great Salt Lake * . 
/ 2,000 
\ to 1,750 
Nyasa ..... 
14,200 
Van* 
2,000 
Tanganyika .... 
12,700 
Albert 
2,000 
Baikal ..... 
11,580 
Tung-ting .... 
1,930 
Great Bear .... 
11,200 
Manitoba .... 
1,850 
Great Slave .... 
10,000 
Urnii * . 
1,750 
Erie 
9,960 
Poyang .... 
1,640 
Winnipeg .... 
9,400 
Bangweolo .... 
1,500 
Ontario .... 
7,240 
Lake of the Woods 
1,500 
Ladoga. ... 
7,000 
Nepigon .... 
1,450 
Balkash .... 
7,000 
Peipus ..... 
1,350 
Nicaragua .... 
4,400 
Kosso-gol .... 
1,300 
Onega ..... 
3,800 
Chapala .... 
1,300 
Rudolf 
3,500 
Tsana 
1,200 
Titicaca .... 
3,200 
Kivu .... 
1,100 
* Lakes marked * are salt. 
