REGION NORTH OF TRENT RIVER 357 



Search has also been made north of Blairton, and of Madoc, near Eldo- 

 rado and Malone, but with no success. In the last locality the hills are 

 quite high enough to receive the beaches, the railway reaching 700 or 

 800 feet above the sea, though keeping to the valleys. The hills are 

 largely rocky — Laurentian more or less capped with flat Ordovician 

 limestones — but there seems to be drift enough to record the beaches if 

 they had been formed. Keluctantly the conclusion was reached that 

 the beach does not extend beyond Havelock toward the northeast; 

 probably because the region was occupied by ice. 



Southwest of Havelock and about a mile west of Trent bridge, a dis- 

 tinct gravel bar is found 75 feet above the river, or 436 feet above Ontario, 

 and others occur at about the same level between this and Hastings, all 

 probably equivalent to one of the lower Iroquois beaches found on the 

 island north of Campbellford at 432 or 442 feet. A bay must have ex- 

 tended southwest along the Trent valley, including Rice lake, but it was 

 so narrow that evidence of wave action is almost wanting. As Rice lake 

 is 370 feet above Ontario, and the distance from Trent bridge to its south- 

 west end is 30 miles nearly in the direction of tilt of the old beach, which 

 is at a rate of not less than 3 feet per mile in this region, the bay can 

 hardly have extended to its extreme end. Its surface must have dipped 

 beneath the present plane of Rice lake, not far from the mouth of Otona- 

 bee river, and as the lake is only 30 feet deep at the deepest point, the 

 southwest end of the bay must have fallen 2 or 3 miles short of the 

 present end of the lake. 



As the southwest end of Rice lake is only 4 or 5 miles from Quay's 

 gravel pit, on the Iroquois beach north of Port Hope, it is evident that 

 the morainic hills to the northeast formed a large peninsula in lake Iro- 

 quois connected with the mainland by a rather narrow isthmus. 



Lake Peterboro 



It was thought at first that Rice lake bay extended an arm along the 

 valley of the Otonabee, which is the northern equivalent of Trent river, 

 as far as Peterboro, but an examination of the ground shows that a short 

 stretch of river confined between drumlins and moraine ridges separated 

 the two bodies of water, so that lake Peterboro must be recognized as 

 distinct from lake Iroquois. 



The lake covered a clay flat toward the south and reached to the north 

 end of the city of Peterboro, a length of about 10 miles. Here a river 

 much larger than the Otonabee entered it from the north, piling up delta 

 deposits of coarse gravel and sand, the highest terrace reaching 432 feet 

 above lake Ontario. This great river was probably the outlet, at least 



