The Glacial Theory. 583 



surfaces of the Braid Hills, first pointed out by Sir James Hall, 

 and which the great chemical geologist attributed to a powerful 

 rush of waters. When I visited the low ridge in question with Dr. 

 Buckland and other friends*, my conviction was that these grooves, 

 though then attributed by Dr. Buckland to glacial action, are due 

 neither to that agency, nor to any rush of waters, but ai-e simply 

 the result of the changes which the mass of the rock underwent, 

 when it passed from its former molten or pasty condition into a 

 solid state. These appearances diifer essentially from ordinary gla- 

 cial scratches or scorings f. They are, in fact, broad undulations 

 or furrows, and instead of trending from the higher grounds to 

 the Firth of Forth, as would naturally be the case if they were due 

 to the expansion and descent of glaciers, they rise up to the very 

 summit of the low ridge in a direction transverse to its bearing, 

 and with no neighbouring point of ground higher than that on 

 which they occur. On clearing away the thin turf which barely co- 

 vered the rock, some of these undulations in the surface appeared 

 wide enough to contain the body of a man, and though observing 

 a rude sort of parallelism, their forms were often devious. As 

 their surface was smooth, not much unlike the usual aspect of 

 the so called "moutonnes" rocks, the glacialists of our party at 

 first seemed to be proving their case, when suddenly a discovery 

 destroyed, at least in my opinion, their theory ; for in the adjacent 

 quarries of the same hill, at a much lower level, and upon beds just 

 uncovered by the workmen from beneath much solid stone, other 

 sets of undulations or grooves were detected, so like to those upon 

 the summit of the hill, that a little atmospheric influence alone was 

 required to complete their identity. My belief therefore is, that the 

 undulations were caused by the action which took place when the 

 stone was solidified. 



Phaenomena of a similar nature to the Scottish have been since 

 observed in Wales by our late Fellow, Mr. Bowman. Capti\ated 

 by the glacial theory, and having himself endeavoured to show that 

 it could even be as, successfully applied to the South as to the 

 North of Scotland, he examined the highest region of Wales, with 

 the geological structure of which he was previously familiar, half 

 convinced, a priori, that he would naturally find in those moun- 

 tainous tracts some proof in support of the new views which he had 

 adopted. He, however, (juitted that country without having been able 

 to observe any evidence whatever in favour of the Alpine theory, 

 though his journey enabled him to detect several examples of striated 

 rocks, which in unskilful hands might have been mistaken for the 

 effects of glacial action ; and these he holds up as warning beacons. 

 After stating that there are, in his opinion, no terraces which any 

 follower of Agassiz can construe into " moraines," whether terminal, 

 medial, or lateral, on the flanks of the mountains of Snowdon, the 

 Arenigs, or the Berwyns, he describes three distinct and ditt'erently 



• Dr. Graham and Mr. Maclaren were of the party, in Oct. 1840. 

 t Plaster casts of these exist in the Geological Society. 



