Upper or Western Canada[148] is marked off from the eastern province by the natural boundary of the Ottawa or Grand River. It consists almost throughout of one uniform plain. In all those districts hitherto settled or explored, there is scarcely a single eminence that can be called a hill, although traversed by two wide ridges, rising above the usual level of the country. The greater of these elevations passes through nearly the whole extent of the province from southeast to northwest, separating the waters falling into the St. Lawrence and the great lakes from those tributary to the Ottawa: the highest point is forty miles north of Kingston, being also the most elevated level on that magnificent modern work, the Rideau Canal;[149] it is 290 feet above the Ottawa at Bytown, and 160 feet higher than the surface of Lake Ontario. Toward these waters the plain descends at the gradient of about four feet in the mile; this declivity is imperceptible to the eye, and is varied by gently undulating slopes and inequalities. Beyond the broad, rich valley lying to the north of this elevation there is a rocky and mountainous country; still farther north are seen snow-covered peaks of a great but unknown height; thence to the pole extends the dreary region of the Hudson Bay territory. The lesser elevation begins near the eastern extremity of Ontario, and runs almost parallel with the shores of the lake to a point about twenty-four miles northwest from Toronto, where it separates the streams flowing into Lakes Huron and Ontario: it then passes southeast between Lakes Erie and Ontario, and terminates on the Genesee in the United States. This has a more perceptible elevation than the southern ridge, and in some places rises into bold heights. The only portion of the vast plain of Western Canada surveyed or effectually explored is included by a line drawn from the eastern coast of Lake Huron to the Ottawa River, and the northern shores of the great chain of lake and river; this is, however, nearly as large as the whole of England.