PEOCEEDIXGS OF GEOLOGICAL SOCIETIES. 
97 
however, being carefully wrought out, and as jMrs. 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 Powbie, F.G.S. 
Roswallie, Fehniary 18th, 1863. 
PEOCEEDINGS OF GEOLOGICAL SOCIETIES. 
Geologtcal Society. — January 2].s^. — 1. " On a Northerly Extension 
of the Upper Silurian ' Passage-beds ' to Linley, Salop." i3y Messrs. 
George E. Eoberts and John Eandall. 
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 Ived clays. The lower bone-bed was stated to be chiefly composed 
of scales of Thelodus and broken Linguloe, and the higher one to contain 
a more than usual abundance of fish-spines ; and it was remarked tliat 
crustacean remains were altogether absent, but Limjula 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 Murcliison 
in his remarks upon the change in the character of the sediments which 
closed the Silurian epoch. The occurrence at Trimplej^ 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. Eoberts, 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 Eoads of Glen Eoy, and their place in the History 
of the Glacial Period." By Professor T. F. Jamieson. 
After describing the general appearance of the roads, the author refi^rrcd 
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 Argyleshire. 
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 
TOL. VI. O 
