No. 1.] DAWSON — POST-PLIOCENE. 27 



the manner of the pavements of boulders described by Miller, as 

 occurring in the Till of Scotland. These appearances are, how- 

 ever, rare, and few opportunities occur for observing them. 



A very general and important appearance is the polishing and 

 striation of the underlying rocks usually to be observed under 

 the Boulder-clay, and which is undoubtedly of the same charac- 

 ter w^ith that observed under Alpine glaciers. This continental 

 striation or grooving is obviously the effect of the action of 

 ice, and its direction marks the course in which the abrading 

 agent travelled. This direction has been ascertained by the 

 Canadian and United States Surveys, and by local observers, 

 over a large part of Eastern America, and it presents some 

 broad features well deserving attention. A valuable table of the 

 direction of this striation is given in the Geology of Canada, 

 which I may take as a basis for my remarks, adding to it a few 

 local observations of my own.^^ The table embraces one hundred 

 and forty five observations, extending along the valleys of the 

 St. Lawrence and the Ottawa and the borders of the sreat lakes. 

 In all of these the direction is south, with an inclination to the 

 West and East, or to state the case more precisely, there are two 

 sets of striae, a South-west set and a South-east set. In the 

 table eighty-four are westward of South and fifty-eight are east- 

 ward of South, three being due South. It further appears, when 

 we mark the localities on the map, that in the valley of the St. 

 Lawrence and the rising grounds bounding it, the prevailing 

 course is South-west, and this is also the prevalent direction in 

 Western New York, and behind the great Laurentide chain on 

 the North side of Lake Huron. Crossing this striation nearly at 

 right angles, is a second set, which occurs in the neck of land 

 between Georgian Bay and Lake Ontario, in the valley of the 

 Ottawa and in the hilly districts of the Eastern Townships of 

 the Province of Quebec, where it is connected with a similar 

 striation which is prevalent in the valleys of Lake Champlain 

 and the Connecticut River and elsewhere in New Enirlaud. In 

 New England this striation is said to have been observed on hills 

 4800 feet high, as for example on Mansfield Mountain, where 

 according to Hitchcock there are striae bearing S. 30° E. at an 

 elevation of 4848 feet. In Nova Scotia and New Brunswick, as 



* See also, for the Western districts, Whittlesey's Memoir in the 

 Smithsonian Contributions, and Newberry's Report on Ohio. 



