Passing over the comparatively poor flora of the earlier Mesozoic, consisting largely of cycads, pines, and ferns, which, as we have seen, is probably of southern origin, and is as yet little known in the arctic, though represented, according to Heer, by the supposed Jurassic flora of Cape Boheman, we find, especially at Komé and Atané in Greenland, an interesting occurrence of those earliest precursors of the truly modern forms of plants which appear in the Cretaceous, the period of the English chalk, and of the New Jersey greensands. There are two plant groups of this age in Greenland, one, that of Komé consists almost entirely of ferns, cycads, and pines, and is of decidedly Mesozoic aspect. This was regarded by Heer as Lower Cretaceous. The other, that of Atané, holds remains of many modern temperate genera, as _Populus_, _Myrica_, _Ficus_, _Sassafras_, and _Magnolia_. This he regards as Middle Cretaceous. Above this is the Patoot series, with many exogenous trees of modern genera, and representing the Upper Cretaceous. Resting upon these Upper Cretaceous beds, without the intervention of any other formation,[94] are beds rich in plants of much more modern appearance, and referred by Heer to the Miocene period, a reference which appeared at the time to be warranted by comparison with the Tertiary plants of Europe, but, as we shall see, not with those of America. Still farther north this so-called Miocene assemblage of plants appears in Spitzbergen and Grinnell Land; but there, owing to the predominance of trees allied to the spruces, it has a decidedly more boreal character than in Greenland, as might be anticipated from its nearer approach to the pole.[95] [94] Nordenskiöld, Expedition to Greenland, _Geological Magazine_, 1872. [95] Yet even here the Bald Cypress (_Taxodium distichum_), or a tree nearly allied to it, is found, though this species is now limited to the Southern States. Fielden and De Ranee, _Journal of Geological Society_, 1878.