_1. Sepulchral Mounds._--This group includes mounds which, originally constructed for other purposes, were afterwards used as burial sites. _2. Refuse Mounds._--This group includes kitchen middens, shell heaps, deposits of waste material remaining after the manufacture of lime, and heaps of stones gathered from the surface of the ground. _3. Foundation Mounds._--As the buildings themselves invariably stood on the summits of flat-topped mounds, such mounds, capped with the débris of the earlier structures, formed the bases of later ones. _4. Defensive Mounds._--Some of these mounds were crescent-shaped; others were in the form of a horseshoe. _5. Lookout Mounds._--These mounds extend in chains, at intervals of 6 to 12 miles, along the coast and up some of the rivers; they are lofty, steep-sided, and usually form the nuclei of groups of other mounds. As a rule they contain neither human remains nor artifacts, though in one or two of them superficial interments seem to have been made at a comparatively late date. _6. Mounds of Uncertain Use._--No trace of human interment was found in these mounds. Many of them are too small at the summit to have supported buildings, and it seems probable that they are sepulchral mounds, in which no stone, pottery, or other indestructible objects were placed with the corpse, and in which the bones have entirely disintegrated. The larger mounds of this class, many of them flat topped, are carefully constructed of blocks of limestone, marl dust, and earth, and no doubt at one time served as bases for buildings either small temples or houses--which, being built of wood, have long since vanished. Most of the mounds are distributed in small and large groups, the latter usually containing one or more examples of each class, the former consisting for the greater part of small burial mounds, probably of late date, as they are less carefully constructed than the mounds of the larger groups, and the objects which they contain are of rougher and cruder workmanship. The burial mounds comprise more than half of all the mounds opened, followed in order of numbers by (a) foundation mounds; (b) mounds of uncertain use; (c) refuse mounds; (d) lookout mounds; (e) defensive mounds. It has been found that, as a rule, rich land contains many mounds; poor land, fewer; and sour-grass savannah, pine ridge, and swamp, none at all. The better the land the more numerous the mounds scattered over it, as is natural, since the more fertile the land the denser the population it would sustain. Not all the mounds opened have been described, as small burial mounds, especially in the same group, in both construction and contents, resemble one another closely, as do foundation mounds also.