14 
MUSEUM BULLETIN NO. 33. 
Lake Ontario presents a problem that is difficult of explanation. 
The uplift which deformed the Algonquin and Iroquois shore- 
lines began after the establishment of the Trent Valley outlet 
and was in part accomplished during the existence of the lakes, 
for the shore r lines diverge in altitude in the direction of maximum 
uplift. The Iroquois shore-lines, however, are not so numerous 
nor do they show so much divergence as those of Lake Algonquin. 
This seems to show that Lake Iroquois was largely drained while 
Lake Algonquin was still in existence. But it does not seem 
possible that the water in the Ontario basin could have fallen 
as low as the present level of Lake Ontario, while the Algonquin 
river was still flowing, for this was far below the level of marine 
submergence. 1 
The outlet channel along the Trent valley below Rice lake 
is well marked near Campbellford, where 20 feet of river gravels 
overlie laminated clays. South of Campbellford at the great 
bend of the Trent a large delta built in a body of standing water 
occurs. North of Frankfort, 10 miles above Trenton, the Trent 
river occupies a deep gorge which has been cut through the 
range of drift hills known as the Murray hills which trend in an 
east and west direction nearly parellel to Lake Ontario. The 
strong outlet channel along the Trent between Frankford and 
Trenton may be due to rapid down-cutting of this channel through 
the drift hills and the consequent releasing of the ponded waters, 
after the disappearance of Lake Iroquois, and may be post- 
Algonquin in age. The size of the outlet channel, however, 
makes this explanation seem doubtful. 
It seems probable that the outlet channel below Rice lake 
is to be correlated with the Otonabee outlet channel. It was 
probably partly formed during the existence of the “two-outlet” 
stage of Lake Algonquin and may be in part post-Algonquin in 
age. Its exact relation to post-Iroquois water-bodies in the 
Ontario basin is not known. 
It was not found possible with the data at present available 
to accurately determine the total fall from Lake Algonquin to 
Lake Iroquois. The fall at the outlet of Lake Algonquin at 
i Coleman, A. P., “Marine and freshwater beaches of Ontario”, Bull. Geol. Soc. Am., 
Vol. 12, 1901. 
