CHARACTERISTICS AND DISTRIBUTION OF LAKES 651 
bear the marks of their origin. Vegetable and animal remains are 
never abundant. Great sandstone beds are always in process of 
formation. The lake-deposits, so far as yet examined, present 
peculiarities which can be detected by the microscope, and are 
largely composed of sandy particles, even when mixed up with salt 
deposited from the salt lakes. There is very little or no organic 
deposit of calcium carbonate. 
II. The Region of Lakes and Rivers draining directly to the 
Ocean. — This covers about 44,000,000 square English miles, or 
about 80 per cent, of the land-surfaces and per cent, of the 
whole surface of the globe. The rainfall is most abundant, and so 
also is vegetable life. Coal and lignite beds have been laid down in 
this region in past ages, and in all the clays, muds, and marls there 
is usually a large admixture of terrestrial organic remains. Lakes 
are not numerous except in places where there has been recent 
glaciation and earth movements. The deposits in the lakes can, on 
examination, usually be distinguished from those formed in inland 
drainage areas. They do not contain any salt deposits, and the 
aspect of the sandy particles is different. 
III. The Littoral and Shallow-Water Region. — This region 
of the ocean, from high-water mark down to a depth of 600 feet, 
covers about 10,000,000 square English miles, or 7 per cent, of the 
water-surface and 5 per cent, of the entire surface of the globe. The 
formations in this region consist of the most varied material derived 
from the land-surfaces and mixed up with the calcareous and siliceous 
materials which have been secreted from the ocean by organisms. 
These consist of boulders, shingles, sands, marls, muds, clays, coral 
reefs, and other calcareous deposits secreted by benthonic animals 
and plants. The action of waves and currents is nearly always to 
be detected. Indeed, the geologist recognises the marks of formations 
laid down in this area more distinctly and more frequently than 
those of any other region, although its area is the smallest of the 
five great divisions. 
IV. The Region of Deep-Sea Terrigenous Deposits. — This area 
lies between a depth of 100 fathoms and the greatest depths within 
200 miles from continental land, embracing all partially enclosed 
seas. It covers an area of 33,000,000 English square miles of the 
sea-floor, or 23 J per cent, of the water-surface and 17 per cent, of 
the entire surface of the globe. It is essentially the area of muds 
and marls, with which are mixed the remains of both plankton and 
benthonic organisms. Quartz grains are abundant in the deposits, 
and glauconite and phosphatic nodules are quite characteristic of the 
area. Chalks and Radiolarian cherts were laid down in this region. 
V. The Abysmal or Pelagic Region of the Ocean. — This em- 
