200 THE WORLD. 



upon the Ganges, at the time of its flood, or in the rainy season, 

 when it is fully charged with sediment, shows that it discharges 

 6,082,041,600 cubic feet in 122 days, and during the three months 

 of hot weather, and the five months winter, it discharges 286,- 

 035,840 cubic feet more, a quantity small compared with the for- 

 mer, the total annual discharge is therefore 6,368,077,440 cubic 

 feet. 



"In order" says Mr. Lyell, "to give some idea of the magni- 

 tude of this result, we will assume that the specific gravity of the 

 dried mud, is only one-half that of granite (it would . however, 

 be more), in that case the earthy matter discharged in a year, 

 would equal 3,184,038,720 cubic feet of granite. Now, about 

 12 cubic feet of granite weigh one ton, and it is computed that 

 the great Pyramid of Egypt, if it were a solid mas^ of granite, 

 would weigh about 6,000,000 tons. The mass of matter there- 

 fore carried down annually, would, according to this estimate, 

 more than equal in weight and bulk forty-two of the great pyra- 

 mids of Egypt, and that borne down in four months of the rains, 

 would equal forty pyramids. The base of the great Pyramid of 

 Egypt covers eloven acres, and its perpendicular height is about 

 five hundred feet. It is scarcely possible to present any picture 

 to the mind which will convey an adequate conception of the 

 mighty scale of this operation, so tranquilly and almost insensi- 

 bly carried on by the Ganges. It may however, be stated, that if 

 a fleet of more than eighty Indiamen, each freighted with about 

 1400 tons weight of mud, were to sail down the river every hour 

 of every day and night for four months continually, they would 

 only transport from the higher country to the sea, a mass of solid 

 matter equal to that borne down by the Ganges in the flood sea- 

 son." 



The same effect is observable in the mighty rivers of America. 

 The Mississippi annually bears down upon its swollen stream in- 

 numerable quantities of trees and sediment, which are imbedded 

 in the basin of the sea at the mouth of the river. In this manner 

 the remains of animals and vegetables are being continually en- 

 veloped, and, should these deltas some day become dryland, the 

 naturalist could determine by a study of the imbedded remains, 



