STRIATED ROCK SURFACES. G9 



throws new light; though Sir William Logan, with his usual caution, 

 has not committed himself t<> theoretical conclusions; and in one or 



two local cases he seems to favour the glacier theory. It has Long 

 been known to geologists, that in north-eastern America, two main 

 directions of striation of rock surfaces occur, from north-east to south- 

 west, and from north-west to south-cast ; and that locally the directions 

 vary from these to north and south and cast and west. Various 

 attempts have been made, but without much success, to account for 

 these directions of striation by the motion of glaciers ; and while it is 

 quite easy for any one prepossessed with this view to account in this 

 way for the striation in a particular valley or part of a valley, yet so 

 many exceptional facts occur as to throw doubt on the explanation, 

 except in the case of a few of the smaller and steeper mountain 

 gorges. 



In the Report of the Survey of Canada a valuable table of these 

 Btriations is given, from which it appears that they are locally 

 distributed in such a way as to throw a decided gleam of light on 

 their origin. 



It would seem that the dominant direction in the valley of the St 

 Lawrence, along the high lands to the north of it, and across western 

 New York, is north-east and south-west ; and that there is another 

 series of scratches running nearly at right angles to the former, across 

 the neck of land between Georgian Bay and Lake Ontario, down the 

 valley of the Ottawa, and across parts of the Eastern Townships, con- 

 necting with the prevalent south and south-cast striation which occurs 

 in the valleys of the Connecticut and Lake Champlain, and elsewhere 

 in New England, as well as in Nova Scotia and New Brunswick. 

 AVhat were the determining conditions of these two courses, and were 

 they contemporaneous or distinct in time '? The first point to be 

 settled in answering these questions is the direction of the force which 

 caused the stria;. Now, I have no hesitation in asserting, from my 

 own observations as well as from those of others, that for the south- 

 west striation the direction was from the ocean toward the interior, 

 against the slope of the St Lawrence valley. The crag-and-tail forms 

 of all our isolated hills, and the direction of transport of boulders 

 carried from them, show that throughout Canada the movement was 

 from north-east to south-west.* This at once disposes of the glacier- 

 theory for the prevailing set of stria; ; for we cannot suppose a glacier 

 moving from the Atlantic up into the interior. On the other hand, it 

 is eminently favourable to the idea of ocean drift. A subsidence of 



* The few exceptional cases appear to belong mostly to the later period of the 

 stratified sands. 



