The sites of the symbolic earthworks of Wisconsin correspond to those adopted by the Mound-Builders for their sacred enclosures; though others of their works, and especially the most remarkable of their animal-mounds, were constructed on prominent heights. Within the fertile region bounded by the great lakes and the Mississippi, a numerous population may have long dwelt undisturbed, in the enjoyment of the profusion which wood and water and the easily cultivated soil supplied. On the bluffs and terraces surmounting the rivers and lakes by which facilities of communication with the surrounding territory, and with more distant regions, were commanded, the earthworks are found in extensive and evidently dependent groups. But, unlike the rich memorial mounds of the Scioto Valley, they reveal few enclosed relics to chronicle the history of their erection, and throw light on the race of artists who laboriously diversified the natural landscape with such devices. In a few cases, human remains have been found in them, under circumstances which did not clearly point to a modern date; but in summing up the results of his explorations, Mr. Lapham remarks:—“So far as I have had opportunity to observe, there are no original remains in the mounds of imitative form, beyond a few scattered fragments that may have gained a place there by accident. Many of the mounds have been entirely removed, including the earth beneath for a considerable depth, in the process of grading streets in Milwaukee; and it is usually found that the natural surface had not been disturbed at the time of the erection, but that the several layers or strata of mould, clay, gravel, etc., are continuous below the structure, as on the contiguous grounds. Great numbers of the smaller conical tumuli are also destitute of any remains; and if human bodies were ever buried under them, they are now so entirely ‘returned to dust’ that no apparent traces of them are left.”[91]