126 LIFE ON THE EARTH. 



all derived in this manner from atmospheric waste 

 of the land, as some suppose. 



For example, the Ganges, which drains 300,000 

 square miles of plains, hills, and mountains, con- 

 taining a great variety of rocky and earthy masses, 

 delivers annually to the Bay of Bengal 6,368,077,440 

 cubic feet of sediment, which is equal to TTT tn f 

 an inch in a year. The maximum thickness of the 

 strata is supposed to be about 72,000 feet = 864,000 

 inches, and dividing this by TiT^h we nave the 

 calculated antiquity of the base of the stratified 

 rocks = 95,904,000 years. But here two things are 

 to be allowed for. The thickness of the old strata 

 is taken at a maximum, and the new deposit is 

 supposed to spread over a much larger space of sea- 

 bed than it really does, so that the period found is 

 something too large. On the other hand, the Ganges 

 carries very much more sediment than some other 

 great rivers, nearly twenty times as much as the 

 Rhine ; it has the character of tropical or excessive 

 effect, and on this account the period may be much 

 too short. 



In whatever way we try the question of the 

 antiquity of the fossiliferous strata, whatever class 

 of phenomena we bring under examination, the re- 

 sults are always the same, always indicative of 

 periods too vast, and we must add too vague, for 



