igoo-i.] Physical Geology of Central Ontario. 175 



that any water which formerly flowed through them must have reached 

 the lowland in front of the cuesta. In many of them the rock scarps 

 which form their sides show no evidences of glacial action. Had the 

 ice advanced up or down them we would expect to find ascending or 

 descending glacial striae. In places there is a systematic arrangement 

 of alternate spurs and re-entrants, producing a tortuous channel, 

 eminently characteristic of stream erosion, but, if we may judge from 

 existing examples elsewhere, such as no ice stream could have passed 

 through. (Compare with the valley of the Rhue, Davis, 1900, 275.) 



The Owen Sound valley, and several others along the Georgian Bay 

 shore, both northwest and southeast of this, in their lower reaches, 

 flare broadly open towards the direction of the ice advance. Striae 

 show that in part they controlled the direction of the ice motion, 

 diverting it, in the Owen Sound case, about fifteen degrees to the east 

 of its general direction. This broadly open portion of the valley was 

 certainly modified by the ice. Along the eastern side of Owen Sound, 

 and similarly in some of the other embayments in the escarpment, 

 there are spurs which have not been removed, while upon the western 

 sides, which received the thrust of the ice, the escarpment presents a 

 much more even face. 



North of Owen Sound in Colpoy's bay, and between Lion's Head 

 and Cape Croker, there are a complicated series of channels, irregular 

 bays, and islands in front of the escarpment. The different channels 

 bear no definite relation to the direction of the ice movement in adjacent 

 regions, some being even transverse to it. There is no evidence of 

 discordance where the smaller side channels join the principal channel. 



Between Owen Sound and Collingwood there are two unsubmerged 

 sinuses extending far inland. Through one of these the Bighead river 

 enters Georgian Bay at Meaford. The other, which reaches back for 

 more than fifteen miles, over eight miles in breadth at the mouth, and 

 about 1,000 feet in depth, is now the valley of the Beaver river, which 

 enters the bay at Thornbury (Plate V, figs, i and 2). Between 

 Collingwood and Hamilton there are a number of similar valleys. The 

 most important of these are those now occupied by the Noisy, Mad, 

 Nottawa, Nottawasaga and Credit rivers, Sixteen -Mile creek and 

 Twelve-Mile creek. A branch of this latter heads on the outlier west of 

 Milton, and through its upper course passes between it and the main 

 escarpment. The largest of all the valleys is that at Dundas, described 

 by Spencer ( '81). (Plate V, fig. 3.) 



