Among others who contributed valuable papers on the subject may be noticed Oswald Heer (1809-1883), who made observations on the Miocene flora, especially in Arctic regions; Gaston de Saporta (1823-1895), who examined the Tertiary flora; Sir J.
Suggested two centuries ago by Robert Hooke, this use of fossils has in the hands of Barrande, Neumayr, the marquis de Saporta (1895), Oswald Heer (1809-1883), and an army of followers developed into a sub-science of vast importance and interest.
The curious genus Dolerophyllum (Saporta) may be mentioned in this connexion.
Williamson was the first to express the opinion that the Bennettitean flowers known as Williamsonia were borne on the trunks which terminated in a crown of pinnate fronds of the type long known as Zamites gigas; this view was regarded by Saporta and others as incorrect, and the nature of the Bennettitean foliage was left an open question.
With the advent of Angiosperms began, as the late marquis of Saporta expressed it, " Une revolution, ainsi rapide dans sa marche qu'universelle dans ses effets."
The earliest Angiosperm yet found in Europe is a single monocotyledonous leaf of doubtful affinities, named by Saporta Alismacites primaevus (fig.
No other undoubted Angiosperm has yet been discovered in Europe in strata of this age, but Heer records a poplar-like leaf from Urgonian strata, a stage newer than the Valenginian, in Greenland, and Saporta has described from strata of the same date in Portugal a Euphorbiaceous plant apparently closely allied to the living Phyllanthus and named by him Choffatia Francheti (fig.
Among the flowering plants are Dewalquea, a ranunculaceous genus already mentioned as occurring in the Upper Cretaceous, and numerous living genera of forest-trees, such as occur throughout the Tertiary period, and are readily comparable with living forms. Saporta has described about seventy Dicotyledons, most of which are peculiar to this locality.
This flora is compared by Saporta and Marion with that of southern Japan.
Other deposits of this age in France have furnished plants of a more varied aspect, including myrtles, araucarias, a bamboo and several fanleaved palms. Saporta points out the presence in these Paleocene deposits of certain types common, on the one hand, to the American Tertiary strata between the Missouri and the Rocky Mountains, and on the other, to the Tertiary flora of Greenland.
In a general way, spiny plants, with stiff branches and dry and coriaceous leaves, dominate the flora, as they now do in Central Africa, to which region on the whole Saporta considers the flora to be most allied.
Saporta considers that in central and southern Europe the alternate dry and moist heat of the Eocene period gave place to a climate more equally and more universally humid, and that these conditions continued without material change into the succeeding Miocene stage.
Therefore the so-called American forms may have originated in the Old World, or more probably, as Saporta suggests, in the polar regions, whence they were driven by the increase of cold southwards into Europe and into America.
The forests of central France during this epoch showed, according to Saporta, a singular admixture of living European species, with trees now characteristic of the Canary Isles and of North America.
De Saporta, " Prodrome d'une flore fossile des Travertins anciens de Sezanne," Mem.
De Saporta and A.