312 THE CANADIAN NATURALIST. [Vol. X. 



Ontario, while at present, the small visible outlet is by Grind- 

 stone creek, through Waterdown. 



Comparing it with Lake Ontario, it has its Niagara escarpment 

 on one side and on the other a gradually shallowing shore towards 

 an area evidently filled to some depth with drift material analo- 

 gous to the soft Cambro-Silurian rocks north of Ontario, whilst 

 its outlet is blocked up, as the the greater lake is, in its south- 

 eastern extremity. 



Thus I will close a fragmentary work, which will, I hope, assist 

 in the study of the surface geology of Ontario, and also give more 

 prominence tu the almost undeveloped subject of Fluviatile 

 Geology. 



(Having learned the value of accurate elevations, I have col- 

 lected the levels of most of the railways in Ontario and some 

 other lists of elevations which will follow the present paper.) 



