G E L .0 G Y, 



THE CRYSTALLINE KOCKS OP THE SCOTTISH HIGHLANDS. 



In the last volume of this Magazine we have had occasion (pp. 

 48 and 140) to report the publication of papers dealing with the 

 important and most interesting problem of the age of the crystal- 

 line rocks of the Scottish Highlands. This problem is reawaken- 

 ing in the attention of geologists, but is only a new phase of a 

 controversy that in past years was carried on between Sir Roderick 

 Murchison on the one hand, and the late Professor Nicol of Aber- 

 deen University on the other. 



The great name of the former geologist procured a general 

 acceptance of his views ; so that for many years they held undis- 

 puted sway, though never yielded to by his opponent, who had 

 personally examined the disputed area. But within the past year 

 or two, interest has again centred itself on the north-west of 

 Scotland, as containing the key to the problem of the age of the 

 Highlands ; and Drs. Lapworth and Callaway have done good 

 service in recalling to the notice of British geologists that the 

 generally accepted view rests on an insufficient basis. In 1883 a 

 party from the Scottish Geological Survey was stationed in Suther- 

 landshire, with instructions to map the Durness district carefully. 

 The results arrived at by them have led to a reversal of Murchi- 

 son's conclusions, and we take this occasion of vindicating in some 

 measure the reputation of one esteemed by all that studied under 

 him, and to draw attention to the acceptance in the main of Pro- 

 fessor Nicol's conclusions even by the Geological Survey, by 

 reprinting from Nature (Nov. 13, 1884) the following article by 

 A. Geikie, F. R. S., the Director of the Survey. The article is of 

 so great value that our readers will be pleased to have it in a 

 magazine, devoted, as this is, to recording advances in Natural 

 Science in all branches in Scotland. — (Ed., Scot. Nat.) 



The article is as follows : 



