548 Remarks on the 



Now in the article under consideration, a period of 3333 years has 

 been assigned, as an approximation for the formation of that portion of 

 the Delta extending from its present limits, to the point situated at 215 

 miles North of Calcutta, which is supposed to have formed the " seaward 

 face," at the time when the lower conglomerate was deposited. Thus 

 leaving only about 1000 years of the historical period to account for 

 the accumulation of all beyond. 



If however, I have assigned the true cause for its formation, it will 

 be seen that the river deposits, which are estimated to amount in bulk 

 to six miles per annum, would have extended themselves over a far wider 

 area than that which has been assigned to them, for the conglomerate 

 which is estimated at sixty feet in thickness is a deposit, not of the 

 rivers, but of the retiring sea, consequently sediments to the amount of 

 sixty feet in depth extending over the whole area below the point as- 

 sumed for the " seaward face," would have been deposited elsewhere. 



But however interesting it may be to note the actual accumulations 

 of the present time, we are, as I have already stated, aware that none 

 can claim a greater antiquity than about 4000 years ; and thus the 

 conjecture of a modern geologist, that the Bramaputra and Ganges 

 have become united within the historical period,* amounts to a mere 

 truism, for if Cuvier shews us, the present rivers have only begun to flow 

 and to deposit alluvial matter since the last order of things commenc- 

 ed, and that commencement is to date from the last retreat of the 

 waters, the above-named rivers could absolutely have become unit- 

 ed in no other period than the historical one, from the simple fact, that 

 from that era, and from that only, can they date their origin. 



That the power which streams of the present day possess of trans- 

 porting detritus is less than they formerly possessed, must be apparent 

 from the reflection that the very plains accumulated by their agency, 

 must naturally raise their beds, and so check their currents, so that al- 

 though now the Bramaputra and the Assam rivers can only carry 

 pebbles to a distance of 25 or 30 miles from the hills, it is very 

 possible, nay even more than probable, that they have once carried 

 them much further. 



" The Adige and the Po, are at the present day higher than the 

 whole tract of land that lies between them ; and it is only by opening 

 new channels for them in the lower grounds, which they have formerly 

 deposited, that the diasters which they now threaten, may be averted. 

 The same causes have produced the same effects along the banks of the 



* Calcutta Journal of Natural History, No. 3, page 454. 



