426 , Bat net 
which measures 120 miles in length by 60 in breadth, is deepest in the southern 
and eastern parts, where a depth of 540 feet has been ascertained, and in con- 
sideration of the area drained by the streams which it receives and the volume 
of water discharged through its outlet, may be regarded as one of the most im- 
portant head-waters of the St. Lawrence. Its largest affluents are the Kayosk 
or Gull River on the west and the Sturgeon River on the east. - 
The second river in point of size on the north shore is the Michipicoten, a 
large clear rapid river which has long served as an important canoe-route to 
Hudson’s Bay. The cther rivers on the east shore are of the same character, receiv- 
ing tributary streams which pour their water through rapids and falls, often of 
considerable height, into the main current. 
Lake Superior discharges its water into Lake Huron through the St. Mary 
River, a stretch of 25 miles, part of which, descending 22 feet in three-quarters of 
a mile, is very rapid, forming the Sault Ste. Marie. The strait so formed where 
it widens into Lake Huron is interruptea by a series of islands which run 
parallel to the north shore and which may be regarded as a continuation of the pro- 
montory into which the Niagara escarpment is continued. These islands, of which 
the chief is Manitoulin Island, together with the promontory referred to, sepa- 
rate the so-called North Channel and the Georgian Bay from the main body of 
the Lake lying to the south. The latter has a surface of 14,000 square miles, 
while the Georgian Bay, from Nottawasaga Bay to Shebanahning (Killarney) 
and the eastern extremity of Grand Manitoulin Island, has been estimated to 
have an area of 6,000 square miles. The North Channel on the other hand, 
exclusive of its islands, has been reckoned to contain 1,700 square miles. As 
before observed, Lake Huron is 22 feet lower than Lake Superior, and therefore 
578 feet above sea level. Its average depth is as great as that of Lake Superior, 
but even greater depths have been ascertained in places—over 1,890 feet having 
been found off Saginaw Bay cn the American side. The greatest length of the 
Lake is 280 miles; its average breadth, 70. Like Lake Superior, it is disting- 
uished, especially in the north-western parts, for the peculiar transparency of 
its waters. 
Emptying themselves into the North Channel and the Georgian Bay are 
the following large rivers :—The Mississaga, the Serpent, the Spanish, the Wah- 
napite, French River, the Maganetawan, and the Severn. The last mentioned 
serves as the outlet of Lake Simcoe, but all of them drain a country studded with 
innumerable lakes and lakelets. The French River has a special importance as 
forming an almost direct line of communication through Lake Nipissing between 
the Upper Lakes and the Ottawa. Its navigation is much obstructed by falls 
and rapids, for in its 40 miles from Lake Nipissing it falls through 87 feet. 
The watershed between Lake Nipissing, the height of which is 665 feet, and 
Upper Trout Lake—the source of the Mattawan, (a branch of the Ottawa)—is 714 
feet high. Lake Nipissing itself is one of the larger inland Jakes, measuring 40 
miles from east to west, and with a maximum breadth of 20 miles from north 
to south. Its area is estimated at 300 square miles. The northern shores of the 
lake are low, generally of flat rock and sand, and the water shallow with a sandy 
bottom. Its principal affluent is the Sturgeon River, a stream of considerable 
size flowing from the north, which forms one of the outlets of Lake Tamaga- 
ming, a fine sheet of water, 800 feet above sea-level, with an area of 330 square 
miles, which has a second outlet towards the Ottawa system through the Montreal 
River. Of the streams flowing from the Province into the main body of Lake 
Huron the most important are the Maitland and the Saugeen. 
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