92 The American Geologist. Feb. i89i 
rise to between 200 and ")50 feet above lake Huron, these measure- 
ments being the extreme variation in their bight. 
From G-eorgian bay to near lake Simcoe, for a distance of thirty 
miles, the country is low ami Hat. with a known absence of rock 
to far below the level of the bay. bake Simcoe is 140 feet above 
Georgian bay, but upon its northern side, at Barrie. a well has 
been sunk in the Drift, without penetrating it, to a depth of 280 
feet below its surface. Thirty miles further inland, south of lake 
Simcoe, at Newmarket, a well was in the process of being bored. 
It had reached a level below Georgian bay and was yet in Drift 
deposits when visited. In another well, several miles to the west- 
ward, near the side of the ancient buried valley at Beeton, rock 
was reached at 50 feet below the surface of Georgian bay. 
Between Newmarket ami Richmond Hill there are several deep 
wells on the heav}' Drift ridges which cross the country. But at 
Richmond Hill, at a hight of 217 feet above Georgian bay, there 
is a well 400 feet deep without penetrating the Drift. This proves 
the thickness of the Drift of the higher ridges crossing the old 
valley north of the well to be not less than 700 feet in the old 
channel. Southward of Richmond Hill the country falls away in 
a series of more or less rolling steppes to lake Ontario, but these 
plains show the absence of rock along deeply-cut valleys to far 
below the level of the upper lakes. Upon the western side of 
this chain of borings, but a few miles distant, there is the Niagara 
escarpment. Upon the eastern side of lake Simcoe the country is 
covered with flat limestones, rising to 150 feet above that lake. 
From the known absence of rocks along the line of borings and 
stream excavations, between a high mountainous escarpment upon 
one side and a rocky floor upon the other, and from these borings 
reaching to 200 feet or more below the upper lakes, without pene- 
trating the Drift but stopping in quicksand, there has been dis- 
covered the existence of the only channel of antiquity which could 
now draw off the waters of the upper lakes, if the Drift were re- 
moved. Although none of the borings have reached the original 
rocky floor, yet the depth of the buried valley is suggested by the 
channel close upon the northern side of lake Ontario, now sub- 
merged to 474 feet, which is deep enough to drain the last drop of 
water out of lake Huron. 
We have now found one continuous channel from lake Michigan 
