PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



97 



however, being carefully wrought out, and as Mrs. Dalgleish has most 

 generously consented to allow still further excavations in the Den, I have 

 little doubt but that this question will be decided during the course of 

 next summer. Yours, etc., 



James Poweie, F.G.S. 



Roswdllie, February \%th, 1863. 



PROCEEDINGS OE GEOLOGICAL SOCIETIES. 



Geological Society. — January 21st. — 1. " On a Northerly Extension 

 of the Upper Silurian 'Passage-beds' to Linley, Salop." By Messrs. 

 George E. Roberts and John Randall. 



Sections obtained along the course of Linley Brook, near Bridgenorth, 

 Salop, were shown to exhibit an ascending series of deposits from 

 Aymestry shales, through Upper Ludlow rock, Downton sandstones (with 

 bone-bed), grey shales and grits (with bone-bed), and plant-bearing shales, 

 to Old Red clays. The lower bone-bed was stated to be chiefly composed 

 of scales of Thelodus and broken Lingulse, and the higher one to contain 

 a more than usual abundance of fish- spines ; and it was remarked that 

 crustacean remains were altogether absent, but Lingula cornea had a 

 range upwards to the Old Red clay. The authors considered the physical 

 conditions of the period to be those indicated by Sir Roderick Murchison 

 in his remarks 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 

 defined basis for the Old Red Sandstone. 



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

 low." By George E. Roberts, Esq. 



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

 stone layer, lying between two bands of cornstone at Bouldon, seven miles 

 north of Ludlow, were exhibited by the author, and doubtfully referred to 

 Hymenocharis. The sandstone in question was stated to be rich in crus- 

 tacean and annelidan tracks and trails. The lower cornstone in the sec- 

 tion 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 Professor T. E. Jamieson. 



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 hypotheses untenable, 

 and pointing out the evidences in favour of Agassiz' theory of a dam of 

 glacier-ice having supported a freshwater 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 submergence during the Drift period, or that 

 the sea did not reach them during the submergence ; also, that it was prior 

 to the formation of the forty-feet raised beach of Argyllshire. 



Professor Jamieson concluded by stating that his examination of Locha- 

 ber had led him to infer that the parallel roads are the beaches of ancient 



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