RELATIONSHIP OF THE LOCAL GROUPS INDICATED 

 BY CORRELATION OF SPECIES. 



To consider the degree of relationship indicated by the groups of plants 

 from the localities which I formerly referred to the Green River Group, I first 

 put in apposition the Flora of the Green River Station and that of Floris- 

 sant, for the specimens have been derived, at each place, from a limited area, 

 and the floras of both are represented by the largest number of species. 



Between these two groups of plants there are only two identical species : 

 Alnus Kefersteinii and Sapindus obtusifolius. The first is one of the most 

 common species of the European Miocene, and not less frequently found 

 in that of North America in California, Oregon, Alaska, and in the Arctic 

 flora of Greenland, Sachalin, &c. It is therefore a Miocene type of a wide 

 distribution, and not a leading plant of a peculiar geological stage. The 

 second species, Sapindus obtusifolius, is most abundant nine miles south- 

 east of Green River Station, at a locality high in the hills, where a thin 

 bed of coal is overlaid with sandy yellow shale filled with the remains of 

 Musophyllum complicatum and Sapindus obtusifolius, mostly; for no other 

 plants were obtained there except a single leaf of Alnus Kefersteinii. 

 This species of Sapindus is so closely allied to S. affinis, Newby., of the 

 Fort Union Group, that it may be considered a mere variety. The leaflets 

 differ only by the more acute points in S. affinis, while in the specimens of 

 Florissant the leaflets are more obtuse than in those of Green River, the 

 difference being apparently local. These two species are therefore Miocene 

 types. Then there are, from Green River Station, Cypern* Chavannesi, 

 Arundo Gcepperti, Phragmites alaskana, Quercus Haidingeri. Salix media, 

 S. elongata, Juglans denticulata, or seven European Miocene species. Of 

 the others, Equisetumwyomingense, Ilex affinis, I. wyomingiana. and a Legu- 

 minosites are closely allied to Miocene types, while Ampelopsis tertiaria, 

 Ficus JJngeri, Myrica nigricans, Arundo reperta have their affinities to 

 species living at our epoch. Hence 17 species out of 24 show evident 

 relationship or identity with plants of the Miocene of Europe or with 



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