PLATE 30, FIGURES 1, 2 "Hicoria n. sp.?" Hollick, Summary Kept. (loc. dt.), p. 134.
These specimens apparently represent sessile leaflets of a compound leaf closely similar to those of certain existing species of hickory, especially Hicoria glabra (Miller) Britton, and H. ovata (Miller) Britton. FIGURE 1 apparently represents two fragmentary, overlapping lateral leaflets, attached to a broken leaf stalk. These present somewhat the appearance of being confluent at their bases, but this appearance is probably due to distortion and overlapping. FIGURE 2 represents a single detached lateral leaflet.
Remains of leaves and nuts of hickories are abundantly represented in American Pleistocene deposits. Leaves referred to Hicoria ovata, under the name Gary a alba Nuttall, from the interglacial deposits of the Don Valley, near Toronto, Canada, were recorded by Penhallow,4 but without any illustration. The same species, represented by two incomplete terminal leaflets, was also recorded by Berry, 5 but not figured, in a list of Pleistocene plant remains, from deposits on the Neuse Kiver, North Carolina. In a subsequent paper the same authors described and figured specimens of leaflets from the Pleistocene of the same State, some of which he referred to Hicoria gldbra (op. cit., p. 106, pl. 46, figs. 1-4), and some to H. ovata (idem, figs. 6, 7). Those referred to H. glabra may be seen to compare quite closely with ours, both in size and general appearance. He also cites Hicoria pseudoglabra Hollick, 7 from the Pleistocene of Maryland, as a synonym of H. glabra. In no instance, however, has a complete leaflet been preserved, and adequate or satisfactory comparison is impossible, either in connection with the fragmentary fossil remains or between them and leaves of existing species. Nuts and husks of Hicoria ovata, and of Hicoria glabra, were also listed by Berry8 from Pleistocene deposits in Virginia, Maryland, and New Jersey; and similar remains, described and figured by Mercer,9 are abundantly represented in deposits of approximately equivalent age, in the so-called "bone caves" of Tennessee and Pennsylvania. It is evident that species of hickory, closely allied to or specifically identical with the existing pignut and shell-bark, were prominent elements in the Pleistocene flora of North America.