l6o UNIVERSITY OF COLORADO STUDIES 



Mr, Scudder designates the Florissant fauna as the Lacustrine Fauna, 

 and the other (including the Green River beds) as the Gosiute Fauna, 

 and then proceeds: 



The difference between the Gosiute and Lacustrine faunas is shown to be much 

 more remarkable when we examine the larger groups. Thus, of the 66 genera 

 found at Florissant, only i8 occur also in the Gosiute fauna, which contains, besides, 

 31 genera not found at Florissant, and there are even a number of tribes which, 

 as far as we yet know, are entirely confined to one or the other fauna. 



Mr. Scudder does not attempt to decide which is the older. 



Turning now to the fishes, the Perciform fishes have five genera, 

 with 18 species, in the Green River beds, but one genus at Florissant, 

 different from all the Green River ones. The Cyprinids have a genus 

 with several species at Florissant, but no member at all in the Green 

 River. The Isospondyli are not at Florissant, but have three Green 

 River genera, one allied to Clupea. There is even a ray (Dasyatis) 

 in 'the Green River beds. While the Florissant fish-fauna is so small 

 and localized that the absence of particular types cannot be considered 

 very important, the presence of types not known in the Green River 

 beds is certainly significant. The evidence from the plants is not 

 so clear, but there is no very close similarity. The presence of an 

 undoubted palm and of a Cinnamomum in the Green River beds sug- 

 gest a warmer chmate than that of the Florissant flora. 



So far as we may judge from the trend of the evidence, and the 

 opinions of Lesquereax and Cope the Florissant beds are later, not 

 earlier, than those of Green River. Scudder (1890), after carefully 

 reviewing the subject, concluded that they belonged "in or near the 

 OUgocene. " More recent writers have been incHned to reject the 

 Ohgocene as a division of our Tertiary, and have referred the Floris- 

 sant beds to the Upper Eocene. My own feehng is, that Lesquereux 's 

 early conclusion was correct, and that they are surely Miocene. Many 

 of the plants are similar to, or even apparently identical with, those 

 well-known to belong to the Miocene period; and that they do not 

 show more resemblance to those of the Pacific region Miocene may 

 be explained as the result of geographical remoteness and a mountain 

 habitat. On the other hand, the resemblances to the plants of older 



