as not yet been time for the rivers to have carved wide
valleys. Thus canoe navigation may be carried on for hundreds of miles,
with here and there a waterfall or a rapid requiring a portage of a few
hundred yards or at most a mile or two. The river systems are therefore
in many cases complex and tortuous, and very often the successive
connecting links between the lakes receive different names. The best
example of this is the familiar one of the St Lawrence, which may be
said to begin as Nipigon river and to take the names St Mary's, St
Clair, Detroit and Niagara, before finally flowing from Lake Ontario to
the sea under its proper name. As these lakes are great reservoirs and
settling basins, the rivers which empty them are unusually steady in
level and contain beautifully clear water. The St Lawrence varies only a
few feet in the year and always has pellucid bluish-green water, while
the Mississippi, whose tributaries begin only a short distance south of
the Great Lakes, varies 40 ft. or more between high- and low-water and
is loaded with mud. The St Lawrence is far the most important Canadian
river from the historic and economic points of view, since it provided
the main artery of exploration in early days, and with its canals past
rapids and between lakes still serves as a great highway of trade
between the interior of the continent and the seaports of Montreal and
Quebec. It is probable that politically Canada would have followed the
course of the States to the south but for the planting of a French
colony with widely extended trading posts along the easily ascended
channel of the St Lawrence and the Great Lakes, so that this river was
the ultimate bond of union between Canada and the empire.

North of the divide between the St Lawrence system and Hudson Bay there
are many large rivers converging on that inland sea, such as Whale
river, Big river, East Main, Rupert and Nottaway rivers coming in from
Ungava and northern Quebec; Moose and Albany rivers with important
tributaries from northern Ontario; and Severn, Nelson and Churchill
rivers from the south-west. All of these are rapid and shallow,
affording navigation only for canoes; but the largest of them, Nelson
river, drains the great Manitoban lakes, Winnipeg, Winnipegosis and
Manitoba, which are frequented by steamers, and receive the waters of
Lake-of-the-Woods, Lake Seul and many others emptying into Winnipeg
river from Ontario; of Red river coming in from the