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Monday, 2d April 1849. 



General Sir T. MAKDOUGALL BRISBANE, Bart., 

 President, in the Chair. 



The following Communication was read : — 



1. On Grooved and Striated Rocks in the Middle Region of 

 Scotland. By Charles Maclaren, Esq. 



In this paper an account was given of grooved, striated, and abraded 

 rocks in various parts of Scotland, from Glen Spean on the north, to 

 the Pentland and Lammennoor Hills on the south. After indicat- 

 ing the direction in which the groovings pointed, it was shewn, — that 

 the appearance of these grooved and striated rocks is irreconcilable 

 with the hypothesis which ascribes the phenomena to a supposed 

 great Atlantic wave or transient flood, of which one part swept across 

 the low lands of Scotland, while another part was turned back by the 

 mountains, — that in the district between the Clyde and the Spean, 

 where the largest and best marked groovings were observed, there is 

 satisfactory evidence to prove, that they were produced by bodies of 

 vast depth occupying the valleys, moving from the mountain group as 

 a common centre, toward the coast and the Lowlands in all direc- 

 tions, and exerting an immense force of pressure vertically and la- 

 terally, — that this quaquaversal motion, as well as the form, position, 

 and size of the groovings, are conclusive against the idea that they 

 were caused by currents of water loaded with stones and gravel, 

 since no collected mass of water exists, or could exist, of the requi- 

 site magnitude and elevation, to send out streams in all directions 

 capable of acting powerfully at the height of a thousand feet or more 

 above the bottoms of the valleys, — that the effects mentioned, there- 

 fore, can only be accounted for by the agency of glaciers, as exemphfied 

 in the Swiss Alps, where glacier ice is found covering immense areas, 

 filling tlie valleys, and grooving and abrading their sides to the height 

 of one or two thousand feet, — finally, that the striae, groovings, and 

 abrasion seen in the great central valley of Scotland, and on the Pent- 

 land Hills, are probably due to icebergs or rafts of ice, to which also 

 the transportation of many travelled boulders may be ascribed. 



