254 The Scottish Naturalist. 



ought to offer an explanation of my own, that it may, in its turn, 

 undergo examination. I labour under the disadvantage, how- 

 ever, of not having studied the drifts in and around Wolver- 

 hampton, &c, and the suggestion which I shall throw out must 

 therefore be taken for what it is worth. It seems to me, then, 

 that the concentration of boulders in the neighbourhood of 

 Wolverhampton, and the limits reached by the northern erratics 

 generally, mark out, in all probability, the line of junction be- 

 tween the vier de glace coming from the basin of the Irish Sea 

 and that flowing across the country from the vast mer de glace 

 that occupied the basin of the German Ocean. Along this line 

 the southerly transport of the northern boulders would cease, 

 and here they would therefore tend to become concentrated. 

 But it is most likely that now and again they would get under- 

 neath the ice-flow that set down the Severn valley, and I should 

 anticipate that they will yet be detected, along with erratics of 

 eastern origin, as far south even as the Bristol Channel. If it 

 be objected to this view that erratics from Great Arenig have 

 been met with south of Wolverhampton, at Birmingham, and 

 Bromsgrove, I would reply that these erratics were probably 

 carried south either before or after the general mer de glace had 

 attained its climax — at a period when the Welsh ice was able to 

 creep out further to the east than it could when the invasion of 

 the North Sea ice was at its height. 



I cannot conclude this paper without expressing my admira- 

 tion for the long-continued and successful labours of the well- 

 known geologist whose views I have been controverting. Al- 

 though I have entered my protest against his iceberg hypothesis, 

 and have freely criticised his theoretical opinions, I most will- 

 ingly admit that the results of his unwearied devotion to the 

 study of those interesting phenomena with which he is so famil- 

 iar have laid all his fellow-workers under a debt of gratitude. 



New British Fungus. — The Puccinia found on Oxyria in Skye, and 

 noticed at page 156, appears to be P. oxyricc Fckl. — a species not hitherto 

 recorded as British. — F. Buchanan White. 



