226 THE CANADIAN NATURALIST. [June, 



striation whicli occurs in the valleys of tlie Connecticut and Lake 

 Champlain, and elsewhere in New England. What were the deter- 

 mining conditions of these two courses, and were they contempo- 

 raneous or distinct in time? The first point to be settled in an- 

 swering these questions, is the direction of the force which caused the 

 strise. Now, I have no hesitation in asserting, from my own 

 observations as well as from those of others, that for the southwest 

 striation the direction was froim 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 dir ction of transport of 

 boulders carried from them, show that throughout Canada the 

 movement was from northeast to southwest.* This at once disposes 

 of the glacier-theory for the prevailing set of striae ; for we cannot 

 suppose a glacier moving from the Atlantic up into the interior. 

 On the other hand, it is eminently favorable to the idea of ocean 

 drift. A subsidence of America, such as would at present convert 

 all the plains of Canada and New York and New England into 

 sea, would determine the course of the Arctic current over this 

 subiner<»-ed land from northeast to southwest : and as the current 

 would move up a slope, the ice which it bore would tend to ground, 

 and to grind the bottom as it passed into shallower water ; for it 

 must be observed that the character of slope which enables a 

 glacier to grind the surface, may prevent ice borne by a current 

 from doing so, and vice versa. 



Now we know that in the Post-pliocene period eastern America 

 was submerged, and consequently the striation at once comes into 

 harmony with other geological facts. We have of course to sup- 

 pose that the striation took place during submergence, and that 

 the process was slow and gradual, beginning near the sea and at 

 the lower levels, and carried upwards to the higher grounds in 

 successive centuries, while the portions previously striated were 

 covered with deposits swept down from the sinking land or dropped 

 from melting ice. It would be easy to show that this view cor- 

 responds with many of the minor facts. 



Farther, the facts thus ascertained account for the excavation 

 of the deep and land-locked basins of our great American lakes. 

 Ocean currents, if cold, and clinging to the bottom, must cut out 

 pot-holes, just as rivers do, though geologists are too apt to 

 limit their iunction to the throwing up of banks. The course 



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

 period of the stratified sands. 



