788 GEOLOGY OF THE YELLOWSTONE NATIONAL PAP.K. 



UtJiensis to Lastrea goldianum, both of which are abundant in the Denver 

 beds of Colorado. Juglans crescentia is related to J. nigella, as identified by 

 Professor Ward in the Fort Union group. The beautiful new Populus 

 xantholithensis is very close to P. genatrix of Newberry, from the Fort 

 Union group. Betula iddingsi is obviously related to B. prisca; Quercus 

 ycmceyi to Q. laurifolia; Platanus montana to P. raynoldsii; Celastrus cidveri 

 to C. ovatus and C. curvinervis ; and Sapindus g rand ifoliolo ides to S. grandi- 

 foliolus, all of the Fort Union group. 



From this evidence it appears that the flora of the early acid breccias 

 in the Yellowstone National Park finds its closest affinity with the flora of 

 the Fort Union group, and it is unhesitatingly referred to that age. The 

 relation of this flora to that of the Laramie is unimportant, being confined 

 to less than half a dozen species. Its relationship to the Denver and Green 

 River floras is naturally closer, but it forms onlj- a small element of these, 

 as also with the flora of the Auriferous gravels of California. The relation, 

 as based on total number of species, is unimportant, but in the upper beds 

 it begins to show a transition. 



It will be next in order to consider the intermediate flora. As already 

 stated, this embraces 30 species, of which number 16 are confined to these 

 beds and 14 are distributed outside, either in the acid or basic series or 

 beyond the limits of the Park. A further analysis brings out the fact that 

 of the 16 species peculiar to these beds 13 are regarded as being new to 

 science, and of the 14 species found beyond the limits of these beds 5 are 

 new to science. This makes a total of 18 species that are regarded as new, 

 leaving 12 species having a distribution without the Park. Following is a 

 complete list of these 12 species: 



Osmunda afflnis Lx. Lauras grandis Lx. 



Sequoia langsdorfii (Brgt.) Heer. Platanus guilleluife Gopp. 



Juglans rugosa Lx. Elteodeudron polymorplmm Ward. 



Ulmus minima Ward. Sapindus affinis Lx. 



Ficus tilia'folia Al. Br. Aralia notata Lx. 



Lauras californica Lx. Aralia wbitneyi Lx. 



Four of the species above enumerated (Sequoia langsdorfii, Juglans 

 rugosa, Platanus guillelmm, and Aralia notata) have a wide distribution, being 

 found from the Laramie to the Upper Miocene, and are therefore of com- 

 paratively little value. One of the remaining (Osmunda affinis) is found in 



