On the Plants of the World before Man. 279 
identifiable with P. Heertt Sap., of the beds of Aix, where it is 
very rare. The predominance of Salvinia, related to European 
Miocene types, is also marked in the Green River group, while 
one species only is described from the beds of Aix, there also 
very rare. We have also from Florissant a large specimen of 
a Sabal, which, like Sabalites major of the beds of Aix, seems 
related to the Miocene Sabal major of Europe. 
, therefore, we consider the relation of the flora of the 
Green River group to that of the Gypseous beds of Aix, merely 
from the number of identical species, it seems to be distant 
indeed, and more evidently marked with the Miocene. But 
then, there is against this conclusion the remarkable affinity in 
the dispersion and fragmentary state of the vegetable remains, 
and a similar facies of the flora apparent in the predominance of 
species of Myrica and other Southern types, like the leaves 
described as Callicoma microphylla, which, as remarked in the 
Tertiary Flora, cannot be referred to this Australian genus, but 
perhaps belong to some peculiar form of Myrica. We have 
also among the vegetable fragments of Florissant, Diospyros, 
Catalpa, Fraxinus, Atlanthus, Paleocarya Engelhardtia, Ulmus, 
Acer, mostly fruits and flowers, as mentioned by Saporta from 
the flora of Aix, leaves of peculiar forms of Quercus, referable 
to Q. salicina and Q. antecedens Sap., and flowers with long 
stamens, which, lacerated though they are, have some likeness to 
those of Bombaz, all from the same flora of Aix. 
But it is useless now to look to points of relation. Not only 
are the specimens from Florissant not yet positively determined, 
but the locality has, in the whole thickness of its shale, merely 
vegetable remains of plants growing around a shallow inlet of 
small area, that of a lake apparently, surrounded for a long 
period of time by the same kind of shrubs and trees, whose 
debris, annually strewn and preserved upon the muddy layer of 
the bottom, does not give a true representation of the general 
vegetation of the land. The American Planera aquatica in- 
habits only some river swamps of Florida and North Carolina. 
Its remains, if found in a fossil state, though they might be 
abundant in a peculiar locality, could not give us the slightest 
idea as to the facies of the land-flora of these regions. The great 
difference and variety in the characters of the plants found at 
other localities of the Green River group, in the deposits of 
Alkali station, of Elko, the mouth of White River and the cut- 
off of Green River, show how little we know as yet of the plants 
of the mighty group, which, like the Gypseous formation of 
Aix, may represent different geological periods at its lower and 
its upper parts. ; 
Passing from the lower beds of Aix to the Oligocene 
(Tongrian for its upper part), Saporta sees in its flora the expo- 
Au aetna < Series, VoL. XVII, No. 100.—Arrit, 1879. 
