in Scotland and Parts of England. 215 



mena of polished and striated surfaces, I may dwell a little 

 longer upon it, mentioning a few examples as yet unre- 

 corded. 



There are, as is well known, some vertical faces of the 

 basaltic clinkstone of Edinburgh Castle rock, which have 

 evidently been polished by some external application. Near 

 this, in the foundation of the Corn Exchange in the Grass- 

 market, Mr David Page found the subjacent rock polished and 

 striated. It is well remembered that, a few years ago, on 

 the cutting out of the superficial detritus on the south 

 shoulder of Arthur's Seat, above Sampson's Ribs, a spot 390 

 feet above the sea, the rock was found to form a kind of 

 trough, the sides and bottom of which were polished and 

 striated. In 1850, some cuttings at the St Margaret's sta- 

 tion of the North British Railway, near Jock's Lodge, enabled 

 me to ascertain that the north base of Arthur's Seat is 

 smoothed and marked in precisely the same manner, namely, 

 "with strise and groovings directed from a point south of 

 west ; while numerous rounded and striated boulders are in- 

 terspersed through the superincumbent compact blue clay, 

 There has lately been a similar exposure of the surface at the 

 parting of the Bathgate and Edinburgh and Glasgow Rail ways 

 at Ratho, and there likewise we see the rock polished and 

 furrowed, while the strise observe a similar direction. In 

 East Lothian, I have found at Whitekirk, at Craig, at Fen- 

 ton Town, and other places, instances of this phenomenon, 

 additional to those previously detected in that county. Pro- 

 fessor Fleming likewise detected glacial surfaces on the west 

 front of North Berwick Law, near the base. The direction 

 of the lines is generally very nearly uniform, namely, from 

 one to two points south of west, being the general direction 

 of the valley. 



There is something in the general configuration of our dis- 

 trict even more remarkable than in these polished surfaces. 

 It is forty years since Sir James Hall observed the peculiar 

 form of eminence which he called crag-and-tail, and of which 

 he pointed out instances in the Abbey Craig and Stirling 

 Castle rocks, in the hill of the Old Town of Edinburgh, and 

 some others. It consisted, as is well known, of an abrupt 



