No. 5.] SPENCER — SURFACE GEOLOGY. 277 



escarpment is abrupt, not having the angle at the summit planed 

 off, except on the western side of Glen Spencer, where 100 feet or 

 more have been removed, by causes to be explained below. The 

 brow of the escarpment on the southern side of the Dundas val- 

 ley and Hamilton is equally abrupt with that on the northern 

 side of the town of Dundas, but the immediate brow is about 

 100 feet lower. Nowhere in the region about Hamilton and 

 Ancaster do we find the face of the escarpment with its angle 

 planed off, although the top is in very many places ice-scratched 

 to the very margin, in directions varying from 10 degrees or less, 

 to 20 deo;rees, with its general trend. 



The geoeral axis of the Dundas valley may be placed at from 

 N 70° E to S 70° W. Nowhere have I observed the striations 

 parallel with its direction, except at about two miles east of An- 

 caster, and at another place at Hamilton ; but this last, at 

 Hamilton, requires further notice. 



At Russel's quarry at the head of James Street, a large 

 amount of clay and rubble, derived from the harder beds of the 

 Clinton (and Niagara also) formation, was removed in order to 

 quarry some of the upper beds of Medina sandstone. This 

 sandstone is overlaid by a few feet of earthy dolomites of the 

 Clinton divisions, these forming a ledge 254 feet above the lake 

 and 134 below the summit of the mountain. Here I observed 

 that the surface had been polished and scratched in the side of 

 the escarpment at a depth of 134 feet, almost vertically below 

 its brow. The direction was S. 80° W, or parallel with this 

 margin of the Dundas valley, or the " Mountain." It is further 

 worthy of remark that although the surface was polished, the 

 striations were very faint. 



VI. — POST PLIOCENE DEPOSITS. . 



Having noticed the general glaciated surfaces of the hard pal- 

 aeozoic rocks of the country, it becomes necessary to study the 

 comparatively modern deposits which rest on them in order to 

 understand the causes which produced the modern topography of 

 the country. 



