LAKE ALGONQUIN. 
15 
Fenelon Falls was approximately 30 feet. At Bobcaygeon 
the fall was about 6 feet. Between this point and Stony lake 
the present fall is 39 feet. It is probable that the ancient fall 
was not as great, for the altitude of the ancient water-plane was 
higher than the present which would have resulted in a drowning 
out of part of the rapids and falls. From Stony Lake basin to 
Rice Lake basin the amount of fall in the ancient Algonquin 
river was equal to the difference in altitude of the correlative 
beaches in the two basins, approximately 175 feet, less the amount 
of uplift. The amount of uplift as determined from the rate 
of tilt of the Iroquois beach in the Rice Lake-Cam pbellford 
district and assuming the direction of tilt to be north 20 degrees 
east is approximately 100 feet. This gives 75 feet as the amount 
of fall in Algonquin river from Stony Lake basin to Rice Lake 
basin. So that it seems probable that the total amount of fall 
from Lake Algonquin to Lake Iroquois, granting that the delta 
at the mouth of Indian river was deposited in Lake Iroquois, 
did not exceed 150 feet. This amount of fall is about 100 feet 
less than the calculated difference in altitude along the same 
isobase, of the highest Algonquin beach in the southern part of 
the Huron basin and of the Iroquois beach in the southwestern 
portion of the Ontario basin. This seems to show that Lake 
Iroquois was contemporaneous with an early stage of Lake 
Algonquin which existed before uplift had raised the level of the 
water in the southern part of the Huron basin and transferred 
the outlet from Fenelon Falls to Port Huron. This confirms 
Gilbert and Taylor’s conclusion that the original Algonquin 
beach is seen only in the region north of the Trent Valley outlet 
isobase and that south of this isobase the beach of this stage was 
considerably lower than the highest beach of the later “two-out- 
let” stage. 
Evidence which further confirms this conclusion as to the 
rise of the Algonquin waters in the southern part of the basin 
was found, by the writer, in the southern portion of Lake Simcoe 
district. Sections exposed on the shore of Lake Simcoe, 2 miles 
east of Jackson point, show a distinct break in the lacustrine 
sands of Lake Algonquin. The sands in the upper portion of 
the section contain numerous fossil freshwater shells of several 
