Lester Ward records no fewer than 737 distinct forms, consisting chiefly of Ferns, Cycads, Conifers and Dicotyledons, the Ferns and Cycads being con fined mainly to the Older Potomac, FIG.
While the Dicotyledons are principally represented in the Newer Potomac, though occurring more rarely even down to the base of the series.
Whatever doubt may be left as to the exact botanical position of these early Lower Cretaceous Angiosperms, it is clear that both Monocotyledons and Dicotyledons are represented by several types of leaves, and that the flora extended over wide areas in North America and Greenland, and is found again at a few points in Europe.
Of the species are Dicotyledons, and that no Monocotyledons have been found.
The genera of Dicotyledons represented are Quercus, Sassafras, Platanus, Celastrophyllum, Cissites, Viburnites.