when we passed, though it was in the second week of the glorious month of May, gave a most unfavourable impression of the land and its climate. Professor Agassiz has pointed out the sub-arctic character of the vegetation of Lake Superior, by a lengthened comparison with the subalpine tracts of Switzerland; but this is due to the nature of the soil, rather than to the elevation or northern position of the district; for as we advance to the north at an equal elevation above the sea, but more to the westward, so as to enter on silurian or newer deposits in the vicinity of the Lake of the Woods and Rainy River, we find cacti and forests having a more southern aspect.

The ascent to the summit of the water-shed between Lakes Superior and Winipeg, by the Kamenistikwoya River, is made by about forty portages, in which the whole or part of a canoe's lading is carried on the men's shoulders; and a greater number occur in the descent to the Winipeg. The summit of the water-shed is an uneven swampy granitic country, so much intersected in every direction by lakes that the water surface considerably exceeds that of the dry land. Its mean elevation above Lake Superior is about eight hundred feet, and the granite knolls and sand-banks, which vary its surface, do not rise more than one hundred and fifty or two hundred feet beyond that general level, though their altitude above the river valleys which

surround them is occasionally greater, giving the district a hilly aspect. The highest of these eminences does not overtop Thunder Mountain and some other basalt-capped promontories on Lake Superior, and had not the silurian strata, which, judging by the patches which remain, once covered the gneiss and granitic rocks nearly to their summits, been removed, the country would have been almost level, and would have formed part of the rolling eastern slope of the continent, above whose plane the highest of the hills on Lake Superior scarcely rises. The summit of this water-shed of the St. Lawrence basin, commencing towards the Labrador coast, runs south 52° west, or about south-west halfwest, at the distance of rather more than two hundred miles from the water-course, until it comes opposite to that elbow of the line of the great lakes which Lake Erie forms; it then takes a north 51° west course, or about north-west half-west, towards the north-east end of Lake Winipeg, and onwards from thence in the same direction to Coronation Gulf of the Arctic Sea. The angle at which the two arms of this extensive water-shed (but no where mountain ridge) meet between Lakes Huron and Ontario is within half a point of a right one, and the character of the surface is every where the same, bearing, in the ramifications and conjunctions of its narrow valleys filled with water, no distant resem

THOUSAND ISLANDS LAKE.

61

Such a

blance to the fiords of the Norway coast. preponderance of fresh water, coupled with the tardy melting of the ice in spring, makes a late summer, and augments the severity of the climate beyond that which is due to the northern position of the district. Though the whole tract is most unfavourable for agriculture, much of the scenery abounds in picturesque beauty. Of this we have an instance in the Thousand Islands Lake, which forms the funnel-shaped outlet of Lake Ontario. At this place the pyrogenous rocks, denuded of newer deposits, cross the river to form a junction with the lofty highlands of the northern counties of New York. The round-backed, wooded hummocks of granite which constitute the more than thousand islets of this expanse of water, are grouped into long vistas, which are alternately disclosed and shut in as we glide smoothly and rapidly among them, in one of the powerful steamers, that carry on the passenger traffic of the lakes. The inferior fertility of this granite belt has deferred the sweeping operations of the settler's axe; the few farm-steadings scattered along the shore enhance the beauty of the forest; and the eye of the traveller finds a pleasant relief in contemplating the scenery, after having dwelt on the monotonous succession of treeless clearances lower down the river. Sooner or later, however, the shores of the Lake of the

Thousand Isles will be studded with the summer retreats of the wealthy citizens of the adjacent states, and the incongruities of taste will mar the fair face of nature.

On the summit of the canoe-route between Lakes Superior and Winipeg, a sheet of water, bearing the analogous appellation of Thousand Lakes, is also studded with knolls of granite, forming islets; but low mural precipices are more common there; and there is, moreover, an intermixture of accumulations of sand, such as are commonly found on the summit of the water-shed, along its whole range. The general scenery of

this lake is similar to that of the Thousand Islands; but though the elevation above the sea does not exceed fourteen hundred feet, the voyagers say that frosts occur on its shores almost every morning throughout the summer.

Silurian strata occur on both flanks of both arms of the water-shed above spoken of, to a greater or smaller extent throughout their whole length.* When we descend to Lake Winipeg we come upon epidotic slates, conglomerates,

* A Pentamerus, very like P. Knightii, was gathered by Dr. Bigsby on the Lake of the Woods, and presented by him to the British Museum. He probably found it in some of the western arms of the lake, the islands in the more easterly part being mostly granite.

sandstones, and trap rocks, similar to those which occur on the northern acclivity of the Lake Superior basin; and after passing the straits of Lake Winipeg, we have the granite rocks on the east shore, and silurian rocks (chiefly bird's-eye limestone) on the west and north, the basin of the lake being mostly excavated in the limestone. The two formations approach nearest to each other at the straits in question, where the limestone, sandstone, epidotic slates, green quartz-rock, greenstone, gneiss, and granite, occur in the close neighbourhood of each other.

The eastern coast-line of Lake Winipeg is in general swampy, with granite knolls rising through the soil, but not to such a height as to render the scenery hilly. The pine forest skirts the shore at the distance of two or three miles, covering gentlyrising lands, and the breadth of continuous lakesurface seems to be in process of diminution, in the following way. A bank of sand is first drifted up, in the line of a chain of rocks which may happen to lie across the mouth of an inlet or deep bay. Carices, balsam-poplars, and willows, speedily take root therein, and the basin which lies behind, cut off from the parent lake, is gradually converted into a marsh by the luxuriant growth of aquatic plants. The sweet gale next appears on its borders, and drift-wood, much of it rotten and