666 MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 



the transport of the oolitic blocks to glaciers. Floating ice alone, in his opinion, 

 afforded a solution. 



In the Isle of Man, Mr Cumming found chalk flints in the boulder-clay, which 

 he thought must have come from the county of Antrim, in Ireland, situated to 

 the N.W. ; and in the drift gravels of the island there were pebbles, which he could 

 only refer to rocks also situated to the N.W.* 



In Ireland, the general direction of the transported boulders is the same as in 

 Scotland and England. Sir Richard Griffith -j- says — " If we look to the distri- 

 bution of erratic blocks, as indicative of the direction of the currents by which 

 they were distributed, we find in Ireland generally that they were carried from 

 N.W. to S.E., though the current was often modified by the opposition of moun- 

 tain ridges." 



" The prevailing direction of our mountain ridges is N.E. and S.W., viz., at 

 right angles to the supposed direction of the current; and, as might be expected, 

 we find the gravel banks and detritus distributed on the N.W. declivities of the 

 hills, and intruding into the interior valleys." 



A later observer, Du Noyer, has identified the boulders lying on the moun- 

 tains near Cork with the granite rocks of Galway, situated on the N.W. coast of 

 Ireland, and has shown that the strise on the smoothed rocks have the same 

 direction.^ 



In the Shetland Islands, an examination was instituted by Mr Peach, at the 

 request of Sir Roderick Murchison, into the drift phenomena. Mr Peach found 

 on the hard primitive rock of the islands, clear evidence of grinding and polishing. 

 The general inference which he drew was, that the agent, whatever it was, must 

 have passed over the islands from the northward. The only exact bearings 

 stated in his report were taken in the island of Unst, the most northern of the 

 group, containing about 36 square miles, and having one hill on it about 500 feet 

 high. The ruts in the rocks there all pointed W.N.W. ; and the side of the hill 

 facing that quarter was (he says) polished to a depth from its top of about 150 

 feet.§ 



In the Faroe Islands, on the N.W. coast, the late Mr Allan,|j when he visited 

 them with Sir George Mackenzie in the year 1812, was struck with a rocky hill, 

 the surface of which appeared " to have been worn down by the friction of heavy 

 bodies" over it. "The rock was scooped and scratched in a very wonderful 

 degree, not only on the horizontal surface, but also on a vertical one of 30 to 40 

 feet, which had been opposed to the current, and presented the same scooped and 

 polished appearance with the rest of the rock." Mr Allan says, " it would be 



* Lond. Geolog. Soc. August 1846, pp. 336 and 342. 



\ British Assoc. Rep. for 1863, vol. xiii. p. 51. 



J Geologist for 1862, p. 246. 



§ British Assoc. Rep. for 1864. 



|| Edin. Roy. Soc. Trans, for 1815, vol. vii. pp. 244-265. 



