38 



of the deep drift in the region around Toronto is of pre- 

 Wisconsin age, but beyond this general statement its precise 

 age has not been determined even approximately, except by 

 Coleman, in the remarkable exposures in Toronto. It is 

 quite clear, however, that the pre- Wisconsin beds or some 

 of them, have a wide extension in easterly, northerly and 

 northwesterly directions from Toronto. In many localities 

 the Wisconsin drift is only a thin sheet, sometimes even dis- 

 continuous, over a great mass of the older drift. The bulky 

 moraines north of Toronto appear to rest upon a deep sub- 

 structure of these older deposits. 



Suburban cars leave the Toronto and York Radial 

 station on North Yonge street. The station stands a little 

 below the level of the beach of glacial lake Iroquois, and the 

 car ascends the old lake cliff immediately after leaving the 

 station. On reaching the top, the traveller finds himself 

 on an undulating plain trenched by small streams running 

 toward the southeast. The stream valleys have been cut 

 to only moderate depths, the deepest being the west branch 

 of the Don river, which at York Mills reaches a depth 

 of about ioo feet. 



The surface forms that meet the eye as soon as the car 

 leaves the old lake bluff are readily recognized as products 

 of glacial action, perhaps partly constructional, but mainly 

 destructional in character — a smoothing and rounding off 

 of an uneven surface by the ice sheet. In the first mile 

 or two several hills resembling drumlins are seen, none of 

 them perfect types, however, but sufficiently near to be 

 called drumloid forms. Glacial action is not recorded alone 

 in these hills, for the whole surface is characterized by long 

 drumloid profiles on the interstream ridges, and the troughs 

 have the same character, and both troughs and ridges are 

 strongly alined after the fashion of drumlins in the direc- 

 tion of the latest ice movement. This kind of surface has 

 been happily characterized by Fairchild as " drumlinized," 

 meaning by this that the drumlin-forming process gave the 

 surface its character, although no perfect drumlins were 

 formed. 



At York Mills the sands in the high bank south of the 

 Don river and west of the track are reported by Coleman 

 to be of pre-Wisconsin age. Between York Mills and Rich- 

 mond Hill several partially drumlinized forms are seen 

 towards the east. At Thornhill a bored well penetrated 600 



