46 THE AMERICAN NATURALIST [Vol. XLIV 



cene, with so much resemblance to even the Basal Eocene, 

 the Florissant flora, to get as far on the other side as its 

 lack of affinity would suggest, would have to be projected 

 somewhere into the future! If this opinion is in any 

 degree correct, Florissant remains as the only Rocky 

 Mountain locality for Miocene plants, so far as known. 



The accompanying figures, all taken from specimens 

 obtained at Florissant by the University of Colorado ex- 

 peditions, will give a good idea of the material from that 

 locality. Xowhere else in America are Tertiary plants 

 so well preserved. As compared with the Eocene flora, 

 and especially the Basal Eocene, the Florissant trees 

 are more diverse in type, with usually smaller leaves, 

 which are often compound. Excessively moist condi- 

 tions are not indicated, though there was evidently much 

 more moisture than at the present day. Some of the 

 plants are even somewhat xerophytic, indicating that the 

 higher slopes may have been relatively dry. Osborn 

 remarks on the evidence of increasing summer droughts 



