1881.) •>Ui [Spencer. 



drift, but it is not absent. On its southern side the steep slopes extend for 

 less than four miles to Ancaster, where they abruptly end in a great de- 

 posit of drift, which there fills the valley to near its summit, but which is 

 partly re-excavated by the modern streams, forming gorges from two to 

 three hundred feet deep. To the north-eastward of Ancaster these gorges 

 are cut down through the drift to nearly the present lake level. 



Westward of Ancaster, a basin occupying a hundred square miles, where 

 the drift is found tc a great depth, forms the western extension of the 

 Dundjis valley. With the north-western and western portions of this drift- 

 fllled area the upper portion of the Grand river and Neith's creek were 

 formerly connected. The Grand river, from Brantford to Seneca, runs 

 near the southern boundary of this basin, then it enters its old valley, which 

 extends from Seneca to Cayuga, with a breadth of two miles, and a depth, 

 in modern times, of seventy-five feet, having its bed but a few feet above 

 the surface of Lake Erie. Near Cayuga, the deepest portion of the river- 

 bed is below the level of Lake Erie. 



2. The Dundas valley and the country westward form a portion of a 

 great river valley, filled with drift. Along and near its present southern 

 margin this drift has been penetrated to 237 feet below the surface of Lake 

 Ontario, thus producing a canon with a lateral depth of 743 feet, but with 

 a computed depth, in the middle of its coui*se, of about 1000 feet. 



3. The Grand river, at four miles south of Gait, has, since the Ice Age, 

 left its ancient bed, which formerly connected with that of the Dundas 

 valle\% as did also Neith's creek, at Paris. 



4. Lake Eiie emptied by a buried channel a few miles westward of the 

 present mouth of the Grand river, and flowed for half a dozen miles to near 

 Cayuga, where it entered the present valley, and continued this channel 

 (reversed) to a place at a short distance westward of Seneca, whence it 

 turned into the basin referred to above, receiving the upper waters of the 

 Grand river and Neith's creek as tributaries, and then emptied into Lake 

 Ontario by the Dundas valley. This channel was also deep enough to 

 dmin Lake Huron. 



5. Throughout nearly the whole length of Lake Ontario, and at no great 

 distance from its southern shore, there is a submerged escarpment (of the 

 Hudson River Formation) which, in magnitude, is comparable with the 

 Niagara escarpment itself, now skirting the lake shore. It was along the 

 foot of this escarpment that the river from the Dundas valley flowed (giving 

 it the present form) to eastward of or near to Oswego, receiving many 

 streams along its course. 



5. The western portion of the Lake Erie basin, the south-western coun- 

 ties of Ontario, and the southern portion of the basin of Lake Huron 

 formed one Preglacial plane, which is now covered with drift or water (or 

 with both) to a depth varying from fifty to one hundred feet, excepting in 

 channels where the filling by drift is very great. A deep channel draining 

 Lake Huron extended through this region, leaving the present lake near 

 the Au Sable river, and entering the Erie basin between Port Stanley and 



