OF THE SEA AND LAND. 19 



the commencement of this process is seen at the influx 

 of every stream. Thus also is the habitable surface 

 of the earth encreased, in these cases, as it is oa the 

 sea ehores ; and that which was the dwelling of fishes 

 becomes a place for man. 



In the higher valleys of hilly countries, the steep sides 

 of the hills become thus fitted for the plough ; while 

 the lodgment of alluvia in their lower parts raises the 

 surface, and produces a fertile plain where there was 

 once a barren declivity. Thus also, in the lower plains, 

 the levels are enlarged ; while additional fertility is 

 conferred by the finer materials which the waters bring 

 down. Thus has been produced the fertile district of 

 Egypt. Divest it of the mud which interior Africa 

 has supplied, and nothing remains but a steep rocky 

 valley, rolling the Nile along, and admitting the sea 

 within its entrance. Hence the fertile plains of Lom- 

 bardy, and the extensive tracts which attend the Plata, 

 the Oroonoko, the Amazon, and the Hudson. Moun- 

 tains useless to man, nearly useless to animals, covered 

 with a scanty vegetation, thus become the seats of 

 nations, regions of fertility, and wealth, and power. 



The connexion between the lowest plains and the 

 aestuaries in which they terminate, is so intimate, that 

 the one is but a part of the other : the limit is a 

 " punctum fluens," where that which is now sea is 

 shortly destined to become land. In these cases, the 

 submarine alluvia, first appearing under the form of 

 banks, and lastly under that of islands, extend the solid 

 plain. Whether in lakes or in the sea, the general 

 process is the same. The Wolga enters the Caspian 

 by seventy mouths, the produce of islands afterwards 

 united^ and of which fresh ones are forming every day. 

 Thus the Sunderbunds first appear as islands, which, 

 uniting, determine a new aperture for the Ganges, or 



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