216 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 22, 



saw through the northern part of this groove from Callander, and 

 saw from under a roof of gray clouds the ends of distant ridges like 

 blue pyramids against a hard yellow sky. I went down the side of 

 the groove to Stirling, and along it to Edinburgh. There I took 

 rubbings off rocks. I saw that which is better shown upon the inch 

 scale. The large rock-groove is fluted by smaller ridges and furrows. 

 When these are examined on the ground, small ice-marks are found 

 wherever they have not been destroyed. Badges of gravel and of 

 Boulder-clay, whose longest axes correspond to rocky hills of like 

 shape, abound from Strathmore to the Clyde, from the " east neuk " 

 of Bife to the west end of Bute. The Bass, North Berwick Law, 

 Edinburgh, Stirling, Dechmont, Dumbarton, Ailsa, and hills which 

 rise through water and drift all the way to the west of Ireland, are 

 alike in form when they are mapped or seen. Any one can see on 

 this map that which I have seen in travelling about for many years. 

 This big Scotch groove is dug out of a great many kinds of rock, as 

 I believe. The softest are in the deepest hollows, and the hardest 

 are generaUy highest. Some broad engine has certainly passed 

 over these low lands. The sea has been there ; for shells are in 

 drift. Ice was there; for Bon lder- clay rests upon glaciated rock. 



Broblems unsolved are, the kind of ice and the extreme size of 

 it, the power which was set to move it, the work which it did, and 

 where and how the work was affected by the material upon which 

 the engine was set to work. 



XY. As to the material. — A series of straight parallel ridges are 

 drawn between Callander and Dumbarton, and contrast some- 

 what with the rest of these forms. At CaUander, at Dumbarton, in 

 Arran, in Antrim, and in Donegal are edges of beds of Old Bed 

 Sandstone. The ridges drawn on the Scotch map are as the grain 

 in carved wood *. At Slieve Liag is a cross section which shows 

 that these beds have been kneaded and crumpled up edgeways like 

 dough. But the forms shown on the map do but record the relative 

 hardness of denuded beds. In the higher country are a different 

 set of forms. Glen Ealloch and Loch Lomond are at right angles to 

 the large groove, and cross the strike of the Old Bed Sandstone, and 

 of the older rocks of the central highlands, of Argyll and Berth. The 

 spurs of Beinn Lomond, parallel to the Loch, are long ridges and 

 furrows which cross the strike and the edges of the Old Bed Sand- 

 stone. Eaults,'and cracks, and breaks abound in the district; but 

 the Ordnance Map and the country itself do not show them. The 

 Geological Maps do ; but the shapes of Scotland and Ireland do not 

 accord with their numerous faults. 



About the head of Glenfalloch, from all the glens and corries 

 about Tigh an Dromma (Bidge House) flow rivulets which go north, 

 south, east, and west through deep glens ; they grow to be rivers, 

 and join the Eorth and Clyde, the Tay and the Awe. In each glen 

 is a flat of water-drift fringed on both sides by rows of hillocks of 

 older glacial drift, containing large smoothed stones of many kinds. 

 At the end of each glen are piles of glacial drift in the form of 

 * A carved mcdel of the hills about Inveraray was shown. 



