5qs proceedings of ttie geological society. [juilc 25, 



June 25, 1873. 



Thomas Douglas, Esq., West Lodge, Crook, Darlington ; Joseph 

 Mitchell, Jun., Esq., Wasbro' Dale, near Barnsley ; Ealph Botley, 

 Esq., of Hindley, near Wigan ; Daniel Ruddle, Esq., 60 Delancey 

 Street, N.W. ; John Dunning, Esq., C.E., Middlesborough ; Thomas 

 Stephens, Esq., M.A., Hobart Town, Tasmania ; and James Willis, 

 Esq., Government Inspector of Mines, Durham, were elected Fellows 

 of the Society. 



The following communications were read : — 



1. On six Lake-basins in Argyllshire. By his Grace the Deke of 

 Argyll, K.T., D.C.L., F.R.S., President. 



The theory of Prof. Bamsay on the origin of lake-basins, and the 

 opposition to it, would do great good if it compelled observers to 

 take note of the exact geological structure of their containing sides. 

 It was as a small contribution to this line of investigation that the 

 author proposed to describe shortly the basins of Loch Eyne and Loch 

 Awe, with some others lying between the two. 



The whole country consists entirely of those mica-slates which 

 have been identified by Sir Roderick Murchison as the equivalents 

 of the Lower Silurian beds which, in the typical section across 

 Sutherland, lie between the Cambrian Sandstones on the west and 

 the Old Red Sandstone on the east coast of that county. The strike 

 of these rocks in Argyllshire is generally from N.E. to S.W. ; and in 

 the district to be described the dip is to the N.W. 



The upper basin of Loch Fyne lies in a long hollow having a 

 general direction parallel to the strike — the northern bank present- 

 ing the escarpment and tbe southern bank the slope side of the 

 strata. Mr. Geikie's geological map of Scotland represents the 

 southern side as composed of the lower, and the northern side as 

 composed of the upper division of the Lower Silurian series. The 

 author has not been able to verify this, nor is he able to say posi- 

 tively that the bed of Loch Fyne occupies a fault. The strata are 

 so like each other that it is difficult to trace faults ; and there is 

 a total absence of organic remains. Mining-operations, however, 

 have shown that the beds are full of faults.. The shores of Loch 

 Fyne are glaciated on all the projecting points, in such a manner 

 as to indicate the action of floating ice coming from the head of the 

 lake. The block of country between it and Loch Awe is also 

 glaciated in a similar manner, not uniformly, but on the projecting 

 points, up to the highest summit — 1700 feet above the level of the 

 sea. The direction from which erratic blocks have come indicates 

 transport from the N.E. 



The upper basin of Loch Fyne, of which the greatest depth is 

 82 fathoms, is sufficiently accounted for when it is seen to oc- 

 cupy a great depression parallel with the general lines of subsi- 

 dence which the strata have evidently undergone. All the neigh- 

 bouring valleys are in the same geological position — one side ex- 



