Geological Society of London. 825 



The Chairman complimented the author on the careful manner in which he had 

 worked out his subject. He thought, however, that many of the principal features 

 described had already been sketched out, though no doubt much knowledge had 

 been added as to details. As to the question of general glaciation, he thought it pro- 

 bable that much of the northern part of Europe had at one time been coated with 

 ice, and to such an extent that it occupied the greater part of the bed of the shallow 

 seas. But even if there were this great ice-sheet, and the general direction of ita 

 flow was from north to south, yet there might in the body of the ice be upper and 

 undercurrents, going to a certain extent in opposite directions, and mainly guided by 

 the surface configuration of the ground beneath. He thought that some trace of this 

 might be found in existing alpine regions, and that, especially in deep valleys, the 

 upper portion of the ice must of necessity have had a tendency to pass over that 

 which occupied the bottom of the valley. With regard to oscillation of temperature 

 and of level, he agreed with the author, and was glad to find that his views as to a 

 submergence of about 2000 feet so nearly corresponded with his own. So long as 

 marine remains were found from stage to stage in a certain class of deposits, the 

 probability of similar deposits at a higher level being also marine, was so great that 

 it almost amounted to certainty. He considered that the importance of the latter 

 part of the Glacial period was liable to be underrated, but it was well evinced by the 

 depth (in some cases amounting to 1400 feet) to which some valleys, such as those of 

 North Wales, appeared to have been filled with ice after the re-emergence of the land. 



Mr. Ward, in reply, stated that, though he had found striations to a height of 2000 

 to 2500 feet, he had not found them on the highest summits of the mountains, where, 

 on the hjrpothesis of a general ice-sheet, they ought to Jiave occurred. He was there- 

 fore not at present prepared to accept the ice -cap theory. In illustration of Prof. 

 Ramsay's view as to the late glacial deposits, he instanced some of the moraines at a 

 high level in the Lake-district, which belonged to the period when the land was still 

 submerged to a depth of 1300 feet or so, and when the cold climate was again 

 supervening. 



2. " Alluvial and Lacustrine Deposits and Alluvial Eecords of the Upper Indus 

 Basin." By Frederic Drew, Esq., F.Gr.S. 



First stating that the alluvium of that country had been noticed by several 

 travellers, especially by Major Grodwin-Austen, who had given much important 

 information about them, the author said that he felt thef necessity for a careful 

 classification of the phenomena of alluvial deposits, for the want of recognition of the 

 different kinds was likely to lead to incorrect deductions ; the classification he pro- 

 posed was the following : — 



I. Loosened Trmterial, which consisted of disjointed rocks or loose angular stones, 

 sometimes mixed up with mud, which had been separated and disintegrated, but since 

 that had remained unmoved. 



II. Taluses, the substance of which had fallen by its own weight, and not been 

 transported by streams. These were the great heaps of angular matter that were 

 found at the foot of cliffs, with a slope generally of near 35°. A special form was the 

 fan-talus, which occurred where the falling matter had either originated from, or 

 collected to, one spot, from which again it spread, and made a partial cone of the same 

 slope as the ordinary taluses. 



III. Alluvial Fans. — These were the fan-shaped extensions of alluvial or torrential 

 matter that spread out from the mouths of gorges, where these debouched into a 

 more open valley. They were in form cones of a low angle, commonly of 5° or so ; 

 they had accumulated by layer after layer on a cone-shaped surface, as shown by the 

 radial sections exhibiting layers of a straight slope, and the chord sections showing 

 curves, which were by the theory hyperbolas. Many complicated phenomena were 

 produced by the denudation of these fans, and the production of secondary ones, 

 some of which were illustrated by diagrams. 



IV. Alluvium, which was defined as a deposit which sloped down 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 deposits. The table- 

 land of Deosai, where the alluvium made flats at an elevation of 12,500 and 13,000 

 feet, surrounded by a ring of mountains of 16,000 and 17,000 feet high, was the most 

 remarkable of these. 



