the enclosure referred to, and in others where careful explorations have been effected. From one, for example, upwards of six hundred disks of hornstone were taken, and it was estimated that the entire deposit numbered little short of four thousand. It thus appears that sacrifices by fire were practised as an important and oft-repeated part of the sacred rites of the Mound-Builders; and also that certain specific and varying purposes were aimed at in the offerings. The altar-mounds are chiefly found within what appear to have been enclosures devoted primarily, if not exclusively, to religious purposes; but they also occur, generally as single works, within the military strongholds: where it may be assumed they sufficed for sacrifices designed to propitiate the objects of national worship, and to win the favour of their deities, when the garrisons were precluded from access to the sacred enclosures where national religious rites were chiefly celebrated. Within a quarter of a mile of “Mound City” a work of somewhat similar outline, but of larger dimensions, suggests the idea of a fortified site: not designed as a military stronghold, but as a walled town, wherein those who officiated at the sacrifices of the adjacent temple may have resided. Unlike the slight enclosure of the latter, its walls are guarded by an outer fosse; and if surmounted by a palisade, or other military work, they were well suited for defence. The area thus enclosed measures twenty-eight acres; and nearly, if not exactly, in the centre is a sacred mound, which covered an altar of singular construction, and with remarkable traces of sacrificial rites. It had undergone repeated changes before its final inhumation. Upon the altar was found an accumulation of burnt remains, carefully covered with a layer of sand, above which was heaped the superstructure of the mound. “The deposit consisted of a thin layer of carbonaceous matter, intermingled with which were some burnt human bones, but so much calcined as to render recognition extremely difficult. Ten well-wrought copper bracelets were also found, placed in two heaps, five in each, and encircling some calcined bones,—probably those of the arms upon which they were worn. Besides these were found a couple of thick plates of mica, placed upon the western slope of the altar.”[88] All investigations coincide in proving that the altars of the Mound-Builders were used for considerable periods, and that their final incovering was effected with systematic care. In this respect they present a striking contrast to the sepulchral mounds of the Indians, the largest and most imposing of which are no more than huge grave-mounds, or earth-pyramids, sometimes elliptical or pear-shaped, but exhibiting in their internal structure no trace of any further design than to heap over the sarcophagus of the honoured chief such a tumulus as should preserve his name and fame to after times.