HEIGHT-OF-LAND, LAKES AND RIVERS. 213 
Along the upper portion of the river several large lakes are encountered, 
often of the nature of river expansions, among which the Grand lake is 
one of the most important. The elevation of this lake is given by Dr 
Bell as about 900 feet above sea, and the height-ofland along the upper 
stretch of the Ottawa as ranging from 850 to 1,050 feet. The ridge sep- 
arating the southern waters from those flowing north is low and sandy, 
and it is probable that the waters of this lake at one time flowed north- 
ward into James bay. Dr Bell remarks on this point that the outflow 
of Grand lake was at one time through the same physical depression in 
which the lake is: now situated, and that this outflow has been arrested 
by the silting up of the channel at the spot where the waters now divide, 
owing to a slow differential elevation of the land to the northeast, which 
is still going on.* 
The greater portion of the area enclosed by the two stretches of the 
Ottawa, east of lake Temiscaming, is occupied by numerous lakes, often 
of large size and frequently with sandy shores. This part of the basin 
is underlain almost entirely by crystalline rocks, chiefly gneisses and 
eranites, with occasional bands of limestone of Archean age. 
To the north of the city of Ottawa the height-ofland is about 250 miles 
distant. The eastern limit of the Ottawa drainage area is marked by the 
waters of North river, which lies northwest of Montreal, and which enters 
Ottawa river about 30 miles west of its junction with the Saint Lawrence. 
The elevation of the height-of-land in this direction, separating the south- 
ern flowing waters from those of the Saint Maurice, is between 1,100 and 
1,200 feet. 
West of lake Temiscaming, which has an elevation of 585 feet, the 
height-of-land between the Ottawa waters and those flowing into James 
bay and into lake Huron is about 50 miles distant. The eastern portion 
of this watershed contains the Montreal river and its tributaries, with 
several large lakes, among which is lake Temagami; the waters of which 
discharge to the south into lake Nipissing and to the northeast into lake 
Temiscaming. The elevation of lake Temagami is, according to Barlow, 
967 feet above sea, and that of the height-of-land to the north of lake 
Temiscaming is about 923 feet. A curving line indicates the watershed 
between the head of Montreal river and lake Nipissing, the elevation of 
the latter being only 645 feet. The elevation again rises eastward of this 
lake till at the source of Petewawa and Madawaska rivers it is about 
1.400 feet, whence it gradually declines toward the Saint Lawrence, 
being only 417 feet at the headwaters of the Rideau. 
South of the Ottawa the area comprised in the drainage basin includes a 
large proportion of the Paleozoic rocks. The western part, in the coun- 
* “ Recent explorations to the south of Hudson bay,” Geographical Journal, July, 1897, pp. 5, 6, 
