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.
It has been found that northern Ontario beyond the divide between the Great Lakes and Hudson Bay possesses many millions of acres of arable land, clay deposits in a post-glacial lake, like those in the southern part of the province, running from east to west from Lake Abitibbi to a point north of Lake Nipigon.
Lake Nipigon, a beautiful body of water 852 ft.
wide, may be looked upon as the headwaters of the St Lawrence, since Nipigon river is the largest tributary of Lake Superior, though several other important rivers, such as the Kaministiquia, the Pic and the Michipicoten, enter it from the north.
The principal rivers on the north shore are the Pigeon, which forms the international boundary line, the Kaministikwia, the Nipigon, which drains the lake of the same name and together with the lake is about 200 m.