Prof. Jamieson on the Parallel Roads of Glen Roy. 237 



remarks of Sir Roderick Murchison upon the change in the character 

 of the sediments which closed the Silurian epoch. The occurrence 

 at Trimpley, and elsewhere, of a cornstone-band in the plant-bearing 

 shales was noted as giving a more denned basis for the Old Red 

 Sandstone. 



2. " On some Crustacean-tracks from the Old Red Sandstone 

 near Ludlow." By George E. Roberts, Esq. 



Tracks of a crustacean found by Mr. Alfred Marston on a thin 

 sandstone layer, lying between two bands of cornstone at Bouldon, 

 7 miles N. of Ludlow, were exhibited by the author, and doubtfully 

 referred to Hymenocaris. The sandstone in question was stated to 

 be rich in crustacean and annelidan tracks and trails. The lower 

 cornstone in the section exhibited at Bouldon was referred to the 

 horizon of the plant-bearing shales of Linley. 



3. " On the Parallel Roads of Glen Roy, and their place in the 

 History of the Glacial Period." By T. F. Jamieson, Esq., F.G.S., 

 Professor of Agriculture in the University of Aberdeen. 



After describing the general appearance of the Roads, the author 

 referred to the different theories that have been framed to account 

 for them, giving his reasons for considering both the marine hypo- 

 theses untenable, and pointing out the evidences in favour of 

 Agassiz's theory of a dam of glacier-ice having supported a fresh- 

 water lake. He especially dwelt upon the coincidence between the 

 height of each of the Parallel Roads and that of a neighbouring 

 watershed, but also remarked upon the objections to a glacial 

 barrier, explaining how it might have shrunk at three successive 

 periods, so as to allow of the formation of the three Roads. He 

 then showed that the period of the formation of these roads must 

 either have been posterior to that of the chief submergence of the 

 Drift-period, or that the sea did not reach them during the sub- 

 mergence ; also, that it was prior to the formation of the 40 feet 

 raised beach of Argyleshire. 



Professor Jamieson concluded by stating that his examination of 

 Lochaber had led him to infer that the Parallel Roads are the 

 beaches of ancient freshwater lakes, which arose from glaciers 

 damming the mouths of the valleys and reversing their drainage, at 

 a date subsequent to that of the great land-glaciation of Scotland, 

 owing to a re-extension of the glaciers after the chief submergence 

 of the Drift-period. 



February 4, 18G3. — Prof. A. C. Ramsay, President, in the Chair. 



The following communications were read : — 



1. " On a Hyaena-den at Wookey Hole, near Wells." — No. II. 

 By W. Boyd Dawkins, Esq., B.A., F.G.S., of the Geological Survey 

 of Great Britain. 



The former but partial exploration of this cave by the author 

 convinced him of the desirability of a more rigorous examination, 

 the details of which were given in this paper, with a Table of the 

 species of Mammalia whose remains were met with (showing the 

 distribution of the teeth and bones in the several parts of the cave), 



