There are large tracts of this north-west country wholly destitute of tree or shrub, and covered only with a luxuriant growth of wild grass, and beautifully interspersed with flowers of every hue and variety, each successively making the prairie to look gay with their presence from April to October. This beautiful natural meadow yields bountiful returns for culture and toil bestowed upon it. It consists of a very dark-brown vegetable mould, and is mellow beyond the conception of those who are acquainted only with the hard, stiff soils of the Atlantic slope. This mould is from one and a half to two feet deep, and entirely free from gravel. The sub-soil is yellow light clay or clay loam, which resembles the soil of timbered lands. The country is a limestone formation. Timber is found only along the streams: it consists of elm, ash, black walnut, butternut, maple, mulberry, and iron-wood, on the bottoms; and on the upland, white, red, black, and burr-oaks, shell-bark and common hickory, with, occasionally, linden, birch, wild-plum and cherry, locust, and some other trees. On the Wisconsin and St. Croix rivers are heavy growths of pine, from which supplies of lumber are carried down the Mississippi river.[61] The mighty rivers of this region must be measured by travel, the prairies must be crossed, and the lakes seen before the mind fully comprehends a description of them. “To look at a prairie up or down,” says Nicollet, “to ascend one of its undulations; to reach a small plateau (or, as the voyageurs call it, a _prairie planché_), moving from wave to wave over alternate swells and depressions; and, finally, to reach the vast interminable low prairie that extends itself in front,—be it for hours, days, or weeks, one never tires; pleasurable and exhilarating sensations are all the time felt; _ennui_ is never experienced. Doubtless there are moments when excessive heat, a want of fresh-water, and other privations, remind one that life is toil; but these drawbacks are of short duration. There is almost always a breeze over them. The security that one feels in knowing that there are no concealed dangers—so vast is the extent which the eye takes in—no difficulties of road; a far spreading verdure, relieved by a profusion of variously coloured flowers; the azure of the sky above, or the tempest that can be seen from its beginning to its end; the beautiful modifications of the changing clouds; the curious looming of objects between earth and sky, taxing the ingenuity every moment to rectify:— all, everything, is calculated to excite the perceptions and keep alive the imagination. In the summer season, especially, everything upon the prairies is cheerful, graceful, and animated. The Indians, with herds of deer, antelope, and buffalo, give life and motion to them. It is then they should be visited; and I pity the man whose soul could remain unmoved under such a scene of excitement.”]