[ 4*7 ] 

 XLV1L Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 38G.] 



June 16th, 1909.— Prof. W. J. Sollas, LL.D., Sc.D., F.E.S., 



President, in the Chair. 



^PHE following communications were read : — 



1. ' The Carboniferous Limestone of County Clare.' By James 

 Archibald Douglas, M.A., B.Sc.,F.G.S. 



2. ' The Howgill Pells and their Topograph}'.' By John Edward 

 Marr, Sc.D., F.R.S., P.G.S., and William George Pearnsides, M.A., 

 F.G.S. 



The Howgill Pells form a monoclinal block, from which the 

 Carboniferous rocks have been denuded. The gentle northern 

 slope probably corresponds very closely with the sloping plane 

 of unconformity between the Carboniferous rocks and the under- 

 lying Lower Paleozoic strata. On the south side, the steep slope 

 to the Rawthey is along a block-fault which has several minor 

 parallel step-faults to the north. The chief drainage was originally 

 north and south from the watershed at the summit of the block, 

 ibut the swifter south-flowing streams have in several cases cap- 

 tured the headwaters of those flowing northwards, and thus the 

 watershed has been largely shifted to the north. Some of these 

 captures occurred probably in pre-Glacial times, but others un- 

 doubtedly took place in the Glacial Period, and others again are still 

 •proceeding. The tract was glaciated by its own ice, but ' foreign ' 

 ice was conterminous with the local ice on all sides. 



The rocks are, from the point of view of erosive effects, nearly 

 homogeneous, and a rounded form of feature was produced by 

 weathering and stream-erosion in pre-Glacial times. The chief 

 erosive effects of glaciation were the truncation of spurs; the 

 formation of conchoidal scoops in the concavities of the valleys ; 

 a general widening of the valleys, and but slight deepening, 

 as marked by the slight difference of grade (amounting to but 

 a few feet) at the junction of tributaries with larger streams. 

 A feature of interest is the contrast in this small area between 

 these glaciated valleys and others of V-shaped cross-section, which 

 are typical water-carved valleys unaffected by glacial erosion. The 

 two great hanging valleys of Uldale and Cauflev, where the streams 

 plunge scores of feet down waterfalls, are due to river-capture, and 

 not to the deepening by ice of the main valleys. 



3. 'A New Species of Sthenurw.' By Ludwig Glauert, F.G.S. 

 L 'Some Reptilian Remains from the Trias of Lossiemouth.' 



By D. M. S. Watson, B.So. 



5. ' Some Reptilian Tracks from the Trias of Runcorn (Cheshire).' 

 By D. M. S. Watson, B.Sc. 



6. ' The Anatomy of LejridopJtloios hricinus, Sternb.' By 

 D. M. S. Watson, B.Sc. 



