630 
THE FRESH-WATER LOCHS OF SCOTLAND 
honour of Louis Agassiz, and must have covered an area of about 
110,000 square miles, exceeding the combined areas of the present 
Laurentian lakes. It discharged southward to the Mississippi, and 
excavated the channel now occupied by Lake Traverse, Big Stone 
Lake, and the Minnesota River ; but as the glacier retreated, and an 
outlet northward was opened up, the level of the waters was gradually 
reduced till the lakes of to-day were left in the deepest portions of its 
basin. This great lake, as measured from its shore-lines, had a 
diameter from north to south of 675 miles, and from east to west of 
about 300 miles, and had a drainage area of about half a million square 
miles. At the site of Lake Winnipeg the ancient lake was 600 feet 
deep. As with the Laurentian glacial lakes, the shore-lines of Lake 
Agassiz now rise northward at a slight inclination, proving that an 
elevation of the land must have taken place during the rise and dis- 
appearance of the ice-sheet. 
Lake of the Woods is the main hydrographical feature of the 
country between Lake Superior and Lake Winnipeg, a district studded 
with lakes and intersected by swift-flowing streams. It is 70 miles 
long, bv 60 miles broad, but its outline is indented to an extraordinary 
degree, and its northern portion is filled with islands. The Lake 
of the Woods lies about 1060 feet above sea-level, and the water 
area is given as 1500 square miles. Its main tributary is Rainy River, 
which flows from Rainy Lake, and its outflow is by Winnipeg River 
to Lake Winnipeg ; there are many rapids in the course of Winnipeg 
River, which is about 163 miles long. 
Lake Winnipeg is about 700 feet above sea-level, 250 miles long 
by 60 miles broad, and has an area of about 9000 square miles ; its 
maximum depth is about 90 feet. On the north-west it receives the 
waters of the Saskatchewan, together with the surplus waters of 
Lakes Winnipegosis and Manitoba. On the east it receives the 
Winnipeg, and on the south the Red River and its tributary, the 
Assiniboine ; the Red River carries to Lake Winnipeg the tribute 
of Lake Traverse, situated on the Minnesota-Dakota boundary, at 
the southern limit of the country formerly flooded by Lake Agassiz, 
and drains through narrow channels sunk in the sediments of the former 
lake. Between the streams there are broad, nearly level inter-stream 
spaces, forming typical examples of new land-areas, on which shallow 
ponds form during rainy seasons. Lake Winnipeg discharges north- 
wards by the Nelson River through several small lakes into Hudson Bay. 
Lake Manitoba lies 810 feet above sea-level, and is connected 
with Lake Winnipeg by the Dauphin River and through St Martin's 
Lake. It is about 120 miles long, from 5 to 30 miles wide, and covers 
an area of 1850 square miles. It is a shallow lake with low shores, 
and very swampy at the southern end, the average depth being 12 feet. 
