WATER-LEVELS DURING LAST ICE ADVANCE 175 



This body of water may have been much deeper than is indicated by 

 the highest stratified materials observed near Toronto. It may even 

 have been part of one of the great postglacial lakes whose beaches have 

 been traced farther west, as, for example, lake Warren ; but it is more 

 probable that the high-level stratified sands and clays were formed be- 

 fore the ice had advanced to its farthest point, in a lake whose beaches 

 were destroyed as the glacier pushed toward the southwest, and so can 

 not be connected with any body of water hitherto described. The highest 

 stratified bed at Scarboro is covered by 30 feet of till, forming the edge 

 of the gently rolling morainic sheet of the country to the north. This 

 brings to an end the succession of interglacial lakes, as shown near 

 Toronto. 



The final retreat of the ice formed lake Warren, of which there are no 

 certain evidences, however, in this region, and at length lake Iroquois, 

 probably the last of the splendid series. 



Conclusions 



Reviewing the old water-levels of the Ontario basin, as sketched in 

 the foregoing paper, we find that the records commence with the Toronto 

 formation at the middle of an inter-Glacial period, and that the succession 

 may be represented in the following table : 



a. Interglacial Lakes 



1. Don stage, warm climate, fresli water shells, dammed by differential elevation 



toward northeast to about 60 feet above present lake. Successor to Lauren- 

 tian river enters north of Toronto. 



2. Scarboro stage, cold temperate climate, fresh water shells, deposits conformable 



with those of last level, but reach 145 feet, and consist of delta materials of 

 Laurentian river. 



3. Low water stage with subaerial erosion and cutting of river valleys to a depth 



below present lake level. 



4. High water stage, glacial or subglacial climate, jirobably fresh water shells, ice 



dammed to a hight of at least 320 feet. 



b. Bodies of Water Accompanying Retreat of Ice 



5. Probably lake Warren, subglacial or cold temperate climate, fresh water shells 



(near Georgian bay), ice dam. 



6. Lake Iroquois, temperate climate, fresh water shells, caribou, wapiti, elephants, 



170 feet above lake Ontario, ice dammed. 



7. Extension of gulf of Saint Lawrence over portions of Ontario basin. 



The series of former water-levels in the Ontario basin as given above 

 must, of course, be looked on merely as relative to the present surface of 



