460 Geological Society : — 



the direction of the valley of the stream which had made it, and 

 did not appreciably slope or curve over in a direction at right angles 

 to that. 



The alluvium of the country in question consisted mostly of 

 pebble-beds, well stratified; it was common at all heights, from 

 16,000 feet or more downwards. Sections of some 100 feet thick 

 were to be observed at intervals along the valleys of most of the 

 rivers : one of 500 feet was described as occurring near Sumkiel, in 

 Rupshu ; and 200, 300, and 400 feet heights of the alluvial terraces 

 above the rivers were very general. 



In a few cases there were wider openings, filled with similar de- 

 posits. The tableland of Deosai, where the alluvium made flats at 

 an elevation of 12,500 and 13,000 feet, surrounded by a ring of 

 mountains 16,000 and 17,000 feet high, was the most remarkable 

 of these. 



A special phenomenon was described as now and then occurriDg 

 in the alluvium, namely a sloping of the alluvial strata, looking at 

 first like false-bedding on a large scale, and, further, a curving or 

 bending of them till they reached round even beyond the perpendi- 

 cular. This the author attributed to the ploughing of the foot of a 

 glacier against the alluvium that had been formed in front of it by 

 its own streams. 



The last class of alluvial deposits would be the lacustrine ; but a 

 description of these was reserved for a future portion of the paper. 



Summary and Inferences. 

 There was evidence of a succession of three states : — 

 1st. The cutting of the valleys. 

 2nd. The accumulation of alluvial matter. 

 3rd. The cutting down of the streams through that alluvial 

 matter. 



Accumulation denotes an excess of supply of material from the 

 rocks (by disintegration^) over what can be carried away by the 

 streams. 



Denudation, or the cutting down of the streams through their 

 alluvium (the lowering of their beds), denotes a deficiency of supply 

 of material from the rocks as compared with the transporting power 

 of the streams. Hence the author inferred that the period of great 

 accumulation of these alluvial deposits was one of great disintegra- 

 tion of rocks, one of intense frost (in other words, it was the 

 Glacial period), and that the denudation occurred when the cold 

 lessened and there came to be a smaller supply of disintegrated 

 material. 



The connexion of various glacial phenomena with the alluvium, 

 such as the one described above, was taken to corroborate the infer- 

 ence that the greater deposits were made during the Glacial epoch. 



