236 Reports and Proceedings — Paheontographical Socief//. 



sides ; hanging lateral valleys ; and glacial overflows. With regard 

 to the first, it is shown that there is no systematic relationship 

 between the height of the cwm-cliffs and the distance of the front 

 rock-step ; the serration of ' cribs ' or aretes cannot be explained by 

 pre-Glacial or post-Glacial weathering according to the protection 

 theory. It is suggested that it might be possible on the erosion 

 theory to work out and classify cwms according to their age and 

 growth, and as a contribution to this enquiry the cwms of Mynydd 

 Mawr are dealt -with. The valley-lakes are likely to be only a small 

 part of the glacial erosion. IS^o consistent explanation of the valley- 

 steps can be found under the theory of ice-protection, -whereas they 

 are explicable on the assumption of glacial erosion. They may have 

 originated in resistant beds, and have then retreated up the valleys. 

 The catenary curve of the cross-section of such valleys as those 

 containing Llyn Gwynant and Llyn Cwellin might be expected to 

 result from long-continued ice-erosion ; and the occurrence of great 

 cliffs on the sides of these valleys is not inconsistent with such an 

 origin. Several good examples of hanging valleys occur, and they 

 seem to show that the deepening of the main valleys by glacial erosion 

 may be from 200 to 400 feet, and in some cases as much as 500 or 

 600 feet. The lateral erosion may easily amount to 1,000 or 1,500 feet. 

 The most striking case of a glacial overflow is that at the head of the 

 Nantlle valley, which appears to have carried much of the West 

 Snowdon ice. The head of the pass would seem to have been farther 

 ■westward and higher in pre-Glacial times. 



II. — Pal^ontographical SociETr. 



fPHE sixty-second annual meeting of this Society was held in the 

 X rooms of the Geological Society, Burlington House, on Friday, 

 March 19, Dr. Henry Woodward, F.R.S., President, in the chair. 

 The Report of the Council referred to the completion of the Monograph 

 of Cretaceous Asteroidea, and to the satisfactory progress of the 

 Monographs of Chalk Fishes, Cretaceous Lamellibranchia, Cambrian 

 Trilobites, and British Graptolites. Numerous proposals for new 

 monographs had been received, but the Council were desirous, so far 

 as possible, to complete those in progress before entering upon further 

 undertakings. The Society had sustained several serious losses by 

 death during the year. The late Mr. W. H. Hudleston was a 

 Vice-President and a distinguished contributor. Professor Albert 

 Gaudry had been a member for manj- years. Sir Thomas AVardle was 

 also an old member, and had served for some time on the Council. 

 An appeal was made for new subscribers to replace these and other 

 members who had been lost. Sir Archibald Geikie, K.C.B., Pres. R. S., 

 was elected a Vice-President in place of the late Mr. Hudleston. 

 Professor E. J. Garwood, Mr. C. Fox-Strangways, and Mr. F. R. 

 Cowper Peed were elected new members of Council. The ofBcers 

 were re-elected — Dr. Henry Woodward as President, Dr. G. J. Hinde 

 as Treasurer, and Dr. A. Smith Woodward as Secretarv. 



