86 TER TIAR Y SYSTEM. 



§ 191. South of the Laurentian Mountains the surface of the rocks beneath the 

 bowlder clay is striated in the direction of the valleys, but there is no connection 

 between these and those occurring north of the mountains in the Hudson's Bay re- 

 gion. The force which produced the scratches did not cross the mountains nor ex- 

 ist upon them. Prof. Dawson has proven the bodies which produced them came 

 from the Atlantic Ocean, and following up the St. Lawrence drifted to the south. 

 at various angles, some floating over New Brunswick, and others over Maine, and 

 others through Lake Cham plain, and re-entering the Atlantic Ocean by the Hudson 

 River, while others were driven beyond Montreal into the mouth of the Ottawa 

 River. In New Brunswick the strise are related to the contour of the surface of the 

 land, and conform to the direction of the river valleys. A south-easterly course 

 prevails in the western part of Charlotte County, and a south-western course in the 

 valleys east and north-east of St. John. A map of Maine showing the course of 

 the rivers will show the course of the striae. The appearance of the surface geology 

 of this State early suggested the fact that a great rush of waters poured over it from 

 a northerly source, and transported by its power the surface d&brii which had ac- 

 cumulated in earlier ages by subaerial forces, and large masses of rock from parent 

 ledges, and deposited them in regions more or less distant from the several sources ; 

 and as they passed along they striated and grooved the rocks against which they im- 

 pinged, or over which they rubbed in the traveled course. The striae conform to 

 the valleys as a rule, and therefore have their courses in all directions, though some 

 are found deflected at right angles to their original course. The Katahdin Mount- 

 ains formed an obstruction around which the striating agency operated, but it did 

 not cross the summit. The strise occur on the north side of the mountains, but not 

 upon the south side. In Vermont, New Hampshire, Massachusetts, and Connecticut, 

 beneath the drift, sand, gravel, bowlders, and clay, the surface of the rocks is grooved 

 and furrowed in a general southern direction, though varying with the contour and 

 course of the valleys. At the Island of New York the current swept from the 

 north-west to the south-east, and the furrows are most strongly marked on the 

 north-western slopes of the hills, and least on the south-eastern. In many instances 

 they are very distinct on the western and north-western slopes, extending to the 

 highest point of the rocks; but no traces exist on the eastern and south-eastern 

 slopes, although both slopes are equally exposed. The strise are most numerous in 

 the middle part of the island, somewhat less in the western, and least in the east- 

 ern, showing the current was deflected southward in the middle part of the island. 

 Throughout all this area south of the Gulf of St. Lawrence and the St. Lawrence 

 Valley, we have, in the strise and furrows and in the distribution of clay, bowlders, 

 gravel, sand, and fossils, the evidence of an overflow of the whole country, except the 

 higher hills and mountains, the overflow resulting from subsidence of the coast, and the 

 evidence that the Arctic current, instead of leaving the coast on approaching the 

 mouth of the gulf, as it does now, flowed into the gulf and across the depressed 

 New England area, transporting its fields of ice, which grounded upon the northern 

 slopes of hills and mountains, and rubbed the rocks in the valleys and plains wher- 

 ever the surface soil and subaerial accumulations were swept off by the grinding 

 weight of a mass, driven by a current through water too shallow to float it. In 

 the Gaspe Peninsula, ocean-terraces and stratified clay, containing marine testacea, 

 occur at the height of 600 feet above the sea. In the Champlain region of Ver- 



