178 THE CANADIAN NATURALIST, [Vol. vi. 



wick, though the agency of a continental glacier is invoked to 

 explain some fjicts which in the sequel we shall find to admit of 

 a different interpretation. 



The travelled and un travelled boulders are usually intermixed 

 in the drift. In some instances, however, the former Jippear to 

 be most numerous near the surface of the mass, and their hori- 

 zontal distribution is also very irregular. In examining coast 

 sections of the drift, we may find for some distance a great abun- 

 dance of angular blocks, with few travelled boulders, or both varie- 

 ties are equally intermixed, or travelled boulders prevail; and we 

 may often observe particular kinds of these last grouped together, 

 as, for instance, a number of blocks of granite, greenstone, syen- 

 ite, etc., all lying together, as if they had been removed from 

 their original beds and all deposited together at one operation. 

 On the surface of the country where the woods have been removed, 

 this arrangement is sometimes equally evident ; thus hundreds of 

 granite boulders may be seen to cumber one limited spot, while 

 in its neighbourhood they are comparatively rare. It is also well 

 known to the farmers in the more rocky districts, that many spots 

 which appear to be covered with boulders have, when these are 

 removed, a layer of soil comparatively free from stones beneath. 

 These appearances may in some instances result from the action 

 of currents of water, which have in spots carried off the sand or 

 clay, leaving the boulders behind ; but in many cases this is mani- 

 festly the original arrangement of the material, the superficial 

 layer of boulders belonging to a more recent driftage than that of 

 the underlying mass in which boulders are often much less abun- 

 dant. 



Boulders or travelled stones are often found in places where 

 there is no other drift. For example, on bare granite hills, about 

 500 feet in height, near St. Mary's River, there are large angular 

 blocks of quartzite, derived from the ridges of that material which 

 abound in the district, but which are separated from the hills on 

 which the fragments lie by deep valleys. 



In Nova Scotia I have observed no beds with marine shells, 

 though the Boulder-clay is often covered with beds of stratified 

 sand and gravel ; and the only evidence of organic life, during 

 the boulder period, or immediately before it, that I have noticed, 

 is a hardened peaty bed which appears under the Boulder-clay on 

 the North-west arm of the River of Inhabitants in Cape Breton. 

 It rests upon gray clay similar to that which underlies peat bogs. 



