first seen with surprise and pleasure; but their uniformity at length becomes tiresome. [65] Eaton's Index to the Geology of the Northern States. First edition.—JAMES. For a few days the weather had been fine, with cool breezes, and broken flying clouds. The shadows of these coursing rapidly over the plain, seemed to put the whole in motion; and we appeared to ourselves as if riding on the unquiet billows of the ocean. The surface is uniformly of the description, not inaptly called _rolling_, and will certainly bear a comparison to the waves of an agitated sea. The distant shores and promontories of woodland, with here and there an insular grove of trees, rendered the illusion more complete. The great extent of country contemplated at a single view, and the unvaried sameness of the surface, made our prospect seem tedious. We pursued our course during the greater part of the day along the same wide plain, and at evening the woody point in which we had encamped on the preceding night was yet discernible. {107} Nothing is more difficult than to estimate, by the eye, the distance of objects seen in these plains. A small animal, as a wolf or a turkey, sometimes appears of the magnitude of a horse, on account of an erroneous impression of distance. Three elk, which were the first we had seen, crossed our path at some distance before us. The effect of the _mirage_, together with our indefinite idea of the distance, magnified these animals to a most prodigious size. For a moment we thought we saw the mastodon of America, moving in those vast plains, which seem to have been created for his dwelling place. An animal seen for the first time, or any object with which the eye is unacquainted, usually appears much enlarged, and inaccurate ideas are formed of the magnitude and distance of all the surrounding objects; but if some well-known animal, as a deer or a wolf, comes into the field of vision so near as to be recognized, the illusions vanish, and all things return to their proper dimensions. Soon after we had left our encampment, on one of the bright sunny mornings which occurred, when we were in the country near the sources of Grand river, we discovered, as we thought, several large animals feeding in the prairie, at the distance of half a mile. These, we believed, could be no other than bisons; and after a consultation respecting the best method of surprising them, two of our party dismounted; and creeping with great care and caution, about one-fourth of a mile through the high grass, arrived near the spot, and discovered an old turkey, with her brood of half-grown young, the only animals now to be seen.