48 Proceedings of the Asiatic Society. [Feb. 



course, and seeks a new channel in the lower ground adjoining — 

 until after successive changes it has gradually wandered over the 

 whole flat and raised the entire surface to the same general level. 

 The same process is then repeated, new channels are cut out, and 

 new deposits formed. Bearing these admitted principles in mind, 

 look to the delta of the Ganges and Brahmaputra. The Ganges 

 river emerging from its upper levels round the Rajmahal Hills, and 

 prevented by their solid rocky barrier from cutting further to the 

 west, sought its channel in the lower ground adjoining — and origi- 

 nally flowed, into the main body of its waters along the general 

 course now indicated by the Bhaghirathi and Hughly. But gradu- 

 ally filling up this channel it was again compelled to seek a new 

 course in the lower, because as yet comparatively unfilled in ground, 

 tying to the east. And the same process being repeated it wand- 

 ered successively from the rocky western limit of the delta-flat 

 towards the eastern. If this progress eastwards was allowed to be 

 sufficiently slow to admit of the gradual filling in of the country ad- 

 joining, the delta was formed continuously up to the same general 

 level, and the larger streams or channels passing through this flat 

 to the sea became unavoidably diminished in size, and in the 

 quantity and force of the water they carried, the main body passing 

 around further to the east, and having its course in the channels 

 successively formed there. I need not here point out the successive 

 stages in the formation of the delta, or shew how these have been 

 exactly paralleled by similar changes in the course and deposits 

 of the Brahmaputra, and the other rivers which unite with the 

 Ganges. We are at present concerned rather with the results 

 arising from these changes as affecting the existence and distribu- 

 tion of popidation. 



The very first necessity for the existence of man is the presence 

 of drinkable sweet water. Whore this cannot be procured, it 

 is certain that man can mako no settlement, — and it is equally 

 certain that the removal or destruction of the sources of supply of 

 this necessary element of existence will compel him to abandon his 

 abode, and change bis habitation. We have not to go beyond the 

 delta of the Ganges itself to see the application of these facts, in 

 explanation of the former history of the Sandarban. Tho more 

 modern course of tho largo rivers give us a patent illustration of 



