228 On the Alpine Glacier, Iceberg, [No. 159. 



The tabular summits of the diamond sandstone and limestone in 

 Southern India are often covered with rounded pebbles, which an ex- 

 amination always proved to be those loosened out of the sandstone pud- 

 ding stones in weathering. 



Diamond gravel. Beds of gravel, in which I have observed trans- 

 ported pebbles which could not be accounted for by causes now in ac- 

 tion, occur in the valley of the Pennaur underlying a steep bed of 

 vegur, and in other diamond tracts. The diamond is found often as a 

 transported pebble in this gravel; and pits are sunk through the regur 

 to it. It is stratified, and bears more resemblance to the gravelly beach 

 of a lake in the size of its pebbles, &c than to the incongruous mass 

 of a boulder bed. It rarely exceeds a couple of feet in thick- 

 ness. 



River terraces, fyc. Along the courses of the great rivers of India, 

 for instance that of the Bhima, are occasionally seen river terraces 

 and beds of gravel beyond the highest present floods and inundations. 

 Some of these may be owing to shifts in the course of the rivers them- 

 selves, but others indicate the passage of more extensive currents of 

 water than at present. 



Captain Allardyce informs me, that the Moyar valley, a mile or 

 more in breadth at the base of the Neilgherries, bears evident marks 

 of having been once the channel of a river, now only visible in an 

 insignificant stream, which even in the monsoon does not occupy one- 

 hundredth part of its breadth. There are beds of sand and gravel 

 in the cross valley of Baugapilly, through which a rivulet cuts its 

 way, which could never have deposited this gravel on the summit 

 of the Ghauts. Captain Allardyce writes me, that traces of a diluvial 

 current exist on the summit of the Neilgherries, upwards of 6,000 feet 

 above the ocean's level ; that the gravel and loam there are arranged 

 in such a manner, as could only take place by deposit from water, 

 the gravel being lowest, in a thin distinct and separate stratum, with 

 the lighter loam covering it to the thickness of several feet. 



Lateritic gravel. Beds of a red ferruginous gravel, principally de- 

 rived from the true laterite, for which they have been mistaken, exist 

 on the table-lands, near the flanks of the Ghauts and in the maritime 

 plains at their bases ; but none of them assimilate the character of the 

 European boulder formation. Some of them are recent alluvia, but 



