416 THE CANADIAN NATURALIST. [Vol. vi. 



would now merely state my belief that some of tbe consid- 

 erations which render it necessary to invoke the action of frost 

 and ice in the Post-pliocene period, apply also to the origin of 

 some rocks of much higher antiquity, Ramsay has already 

 noticed this in the case of the Permian conglomerates of England. 

 In Canada an instance occurs in the cono-lomerate with boulders 

 two feet in diameter, found in the Lower Silurian of Maimanse, 

 Lake Superior,* A still more remarkable case is that of the New 

 Glasgow conglomerate in the coal formation of Nova Scotia, 

 which seems to be a o-ijrantic esker, on the outside of which 

 large travelled boulders were deposited, probably by drift ice, while 

 in the swamps within, the coal flora flourished and fine mud and 

 coaly matter were accumulated. f 



A second indication of the existence of intense frost in ancient 

 geological periods, is aff"orded by the occurrence of angular frag- 

 ments of hard rocks cemented together. Such beds of angular 

 fragments and chips, occur locally at various horizons, for ex- 

 ample in the Upper Silurian and Lower Carboniferous in Nova 

 Scotia, and the material of which they are composed seems pre- 

 cisely similar to that which is at present produced by the disin- 

 tegrating action of frost on hard and especially schistose and 

 jointed rocks. Such deposits may, I think, fairly be regarded as 

 evidence of somewhat intense winter cold. 



Supplementary Note, — A visit to Nova Scotia while these 

 sheets were going through the press enables me to add the follow- 

 ing facts: (1.) The discovery by Mr, Gr. F. Matthews of shells 

 of Tellina Groenlandica in the Post-pliocene gravel at Horton 

 Bluff, Nova Scotia. (2.) The occurrence of Laureutian boul- 

 ders, probably from Labrador, in the Carboniferous region of 

 Nova Scotia. I may specially mention a very fine boulder of 

 Labradorite near the mouth of Carribou River, Pictou County. 

 In Nova Scotia, however, as well as in Prince Edward Island, 

 native stones predominate in the lower Boulder-clay, and the 

 foreign blocks appear more toward the surface ; where also, in 

 many cases the greater part of the blocks derived from neigh- 

 bouring heights are collected. I had occasion often to notice the 

 fact, referred to above, of drift from the south as well as from 

 the north, and also the great frequency in the boulder deposits 

 of glaciated stones. 



* Can, Nat, II, p, 6. f Acadian Geology, p. 324. 



