58 



THE WONDERS OF GEOLOGY. Lect. I. 



From experiments made with great care, it has been 

 ascertained that the quantity of solid matter brought down 

 by the Ganges and carried into the sea annually, is 

 6,368,077,440 tons : in other words, a mass of solid 

 materials, surpassing in size and weight sixty times that 

 of the great pyramid of Egypt ; the base of that stu- 

 pendous structure covering eleven acres, and its perpen- 

 dicular height being 500 feet.* The Burrampooter, 

 another river in India, conveys annually as much earthy 

 matter into the sea as the Ganges. The waters of the 

 Indus, as the late Sir Alexander Burns informed me, are 

 alike loaded with earthy materials. In the vast rivers of 

 America, the same effects are observable ; the Mississippi, 

 which flows through twenty degrees of latitude and seven 

 of longitude, and drains a valley 3,000 miles long and 

 nearly 1,000 broad, brings down whole forests and immense 

 rafts, composed of trunks and branches of trees, and drifted 

 underwood, and transports them to its delta, which extends 

 several hundred miles out to sea; and the basin around the 

 embouchure of that river is becoming shallower every day, 

 by the sole agency of the causes now under consideration. 

 The delta of this mighty stream is computed by Mr. Lyell 

 to be at least between 500 and 600 feet in depth, the area 

 it covers nearly 14,000 square statute miles, and the solid 

 matter annually added 2 billions 700 millions of cubic feet ; 

 and the period required for the formation of the deposits 

 now composing the delta, at more than 60,000 years. f 



In the sediments of these rivers, remains of the animals 

 and plants of the respective countries are continually en- 

 veloped. It is therefore evident, that should the deltas 

 become dry land, the naturalist could, by an examination 

 of the animal and vegetable remains imbedded in the 



* Lyell's Principles of Geology. 



t Lecture on the Delta of the Mississippi, before the British Asso- 

 ciation, at Southampton, 1S46. 



