CENTRAL ONTARIO 225 



is at the same level as lake Ontario and to which most of the larger 

 streams in this part of Ontario are tributary. 



CENTRAL ONTARIO SECTION 



What is usually considered as the headwaters of the main stream of 

 the Trent system is a small lake near the main divide in central Hali- 

 burton county. From this lake a stream, the Gull river, makes its way 

 southwesterly, alternately flowing in valleys between Archean ridges or 

 expanding into small lakes in these valleys, and traversing the ridges 

 in a more or less southeasterly direction, usually in a series of falls or 

 rapids into the next adjacent valley eastward. Just to the east of 

 Norland, where the river expands to form Mud Turtle lake, it enters 

 the Black Eiver cuesta. The islands and shores of Mud Turtle lake are 

 usually of Archean rock, but a little distance back from the shore, on 

 either side, is a limestone escarpment, which reaches its best develop- 

 ment and is highest (125 feet) on the west. This escarpment, whose 

 height above the river gradually diminishes as we proceed downstream, 

 borders the river to below Coboconc at the head of Balsam lake. Here 

 it is lost among drift deposits. 



Balsam lake is a broad, shallow depression on the Black River cuesta. 

 To the west the rock divide between it and lake Simcoe is but 5 feet 

 above ordinary lake-level, while the surface of Balsam lake is about 60 

 feet above lake Simcoe. Whether the Balsam Lake depression is to be 

 considered one of the partly blocked valleys of the pre-Glacial topog- 

 raphy is doubtful. In certain features it seems to be composed of two 

 of these, but at present this must be regarded as uncertain. About 4 

 miles south of Kinmount a small stream, Corben creek, enters it from 

 the northeast. This creek comes from Four Mile lake, a lake occupying 

 the head of one of the valleys of the first type described above, the upper 

 end of the lake being located on Archean rock and the sides of the lake 

 depression being limestone. 



The waters of Balsam lake flow eastward in a shallow channel, cut 

 chiefly in drift deposits, though one broad limestone ledge, a part of the 

 typical flat-topped intervalley upland area, has been discovered by the 

 river. The distance to the next lake on the main system, Cameron lake, 

 is about 2 miles. Cameron lake is an oval body of water occupying a 

 depression which is blocked to the south by drift deposits. The Burnt 

 river, which rises on the Archean areas to the northwest, passes into the 

 Black River cuesta through a deep reentrant about 6 miles to the north- 

 east and enters Cameron lake at the same place as the discharge from 

 Balsam lake. The Cameron Lake depression is really the lower part of 

 the valley of the Burnt river, a valley of the first type here described. 



