﻿272 Canadian Record of Science. 



stituents, and possessing a structure resembling somewhat 

 that of a fine-grained pegmatite. 



No other occurrences of crystalline limestone were 

 observed. 



The dykes described by Dr. Smythe are well exposed 

 on many of the islands, as, for instance, on Lemon, Little 

 John, and No. 14. One long dyke starting from Bluff 

 Island can be observed crossing No. 19, which is made up 

 almost entirely of it, and No. 18 to No. 16, where it seems 

 to terminate. There are, however, probably about thirty 

 of these dykes in all, having a general north and south 

 course and a nearly vertical attitude. Taken together 

 they would be equivalent to a sheet of diabase about 300 

 feet thick. Some of these dykes consist of ordinary 

 diabase and some of olivine diabase. The fact that they 

 are finer in grain toward the sides proves that the 

 gneisses and granites, through which they cut, were cool 

 at the time of their intrusion. They do not cut the 

 Potsdam Sandstone, and are, therefore, older than the 

 Upper Cambrian, while, as Dr. Smythe observes, the 

 absence of any considerable evidences of dynamo- 

 metamorphism in them demonstrates that, during the 

 great length of time which has elapsed since the intrusion 

 of the dykes, the region has not been affected to any great 

 extent by mountain-making forces. 



Modern Attainments in Geology. 



A Lecture Delivered Before the Natural History Society of 

 GoRLiTZ, BY Prof. Edward Suess, of Berlin. 



Translated for The Canadian Record of Science 

 by Nevil Norton Evans, M.A.Sc. 



Ladies and Gentlemen : 



I am to address you upon modern attainments in geology, 

 that is, I am to conduct you to the limits of our science. 



