[Various (1971)] Beginning about 4000 B.C., the warmer climatic conditions of the Xerothermic period were attended first, by an oak-pine, then by an oak-hickory forest succession, both highly favorable as habitats for the most valued game animals, especially the mast eaters, like the deer and turkey (Ritchie 1965a: 16-19; 1969b: 212-213). A similar explanation of the facts has been expressed by James E. Fitting (1968). Staten Island lies at the northern extremity of the Carolinian biotic zone, which enjoys a higher average temperature and a somewhat different floral-faunal association than the Canadian biotic zone adjoining it on the north and including most of the Northeast (Dice 1943). The assumption, on current evidence, is that man in an Early Archaic level of cultural adaptation to a mixed deciduous forest setting, gradually spread northward from the central Appalachian region to the limits of the biotic zone to which he was adjusted and, only rarely, possibly in the most favorable seasons, pushed farther north on hunting or gathering forays into new territories where more propitious forest conditions were gradually replacing the dense stands of conifers. A still largely unknown, weak and scattered occupation of later (Middle?) Archaic hunters, equipped with large, broad-bladed, side-notched points, seems to have followed the Early Archaic groups, probably from the same southern direction, since their slender traces have been found in the lower Hudson Valley.