March, 1849. GEOLOGY OF THE TEKAI. 379 



not the case with the main body of the deposit, which is 

 un stratified, and much coarser. 



The alluvium of the Gangetic valley is both interstrati- 

 fied with the gravel, and passes into it, and was no doubt 

 deposited in deep water, whilst the coarser matter * was 

 accumulating at the foot of the mountains. 



This view is self-evident, and has occurred, I believe, 

 to almost every observer, at whatever part of the base of 

 the Himalaya he may have studied this deposit. Its position, 

 above the sandstones of the Sewalik range in the north- 

 west Himalaya, and those of Sikkim, which appear to be 

 modern fossiliferous rocks, indicates its being geologically 

 of recent formation \ but it still remains a subject of the 

 utmost importance to discover the extent and nature of the 

 ocean to whose agency it is referred. I have elsewhere 

 remarked that the alluvium of the Gangetic valley may 

 to a great degree be the measure of the denudation which 

 the Himalaya has suffered along its Indian watershed. It 

 was, no doubt, during the gradual rise of that chain from 

 the ocean, that the gravel and alluvium were deposited ; 

 and in the terraces and alternation of these, there is 

 evidence that there have been many subsidences and 

 elevations of the coast-line, during which the gravel has 

 suffered greatly from denudation. 



I have never looked at the Sikkim Himalaya from the 

 plains without comparing its bold spurs enclosing sinuous 

 river gorges, to the weather-beaten front of a mountainous 

 coast ; and in following any of its great rivers, the scenery 



* This, too, is non-fossiliferous, and is of unknown depth, except at Calcutta, 

 where the sand and clay beds have been bored through, to the depth of 120 

 feet, below which the first pebbles were met with. Whence these pebbles were 

 derived is a curious problem. The great Himalayan rivers convey pebbles but 

 a very few miles from the mountains on to the plains of India ; and there is no 

 rock in situ above the surface, within many miles of Calcutta, in any direction. 



