454 Remarks on the Deposits 



Ganges to be about 6,368,077,440 cubic feet, which, supposing 

 it to be deposited on a surface as much below the level of 

 the sea as the depth attained in the Fort, would be sufficient 

 annually to raise 6 square miles of dry land ; and if we sup- 

 pose the Bramaputra to contribute equally with the Ganges, 

 these two rivers would require a period of 3,333 years, 

 to extend their delta to its present position from the point 

 it would have occupied (according to the present state of 

 things) at the period when the lower beds penetrated in the 

 Fort were deposited. Mr. Lyell remarked, that the Ganges 

 and Burrampooter have probably become confluent within 

 the historical era, and the foregoing observation rather 

 tends to confirm the conjecture. We have also to remark in the 

 consideration of this question, that the bones brought up 

 from a depth of 350 to 430 feet had not lost all their animal 

 matter ; that is to say, they retained the character of grave 

 bones, and could not therefore be regarded as perfectly 

 fossilized, and the wood which was found at a depth of 390 

 feet retained its recent appearance. When we say 3,333 years 

 as the probable period since the deposits penetrated in Fort 

 William were forming, of course we only mean this as an 

 approximation to the truth. The accuracy of the calculation 

 will, however, depend on the estimate we have formed of the 

 depth of the delta, and the quantity of mud annually dis- 

 charged, as well as on the question whether the sedimentary 

 deposits were the same at the early period alluded to as 

 now, and whether they have been accelerated or interrupted 

 during the interval.* 



Taking the two first of these elements to be nearly as 

 accurate as the present state of our knowledge admits, we 



* We [have just perused an interesting paper by Sir J. G. Wilkinson 

 on the deposits of the Nile, which may lead to some modification of the 

 present views of geologists regarding the growth of Deltas. We shall 

 take an early opportunity of laying the result of Sir J. G. Wilkinson's 

 observations before our readers.— -Ed. Cal. Jour. Nat. Hist. 



