AURIFEROUS GRAVELS— INDEPENDENCE HILL FLORA 889 



fragmentary leaf has been compared to Finis planicostata Lx., 

 a typical Laramie species, but the material is insufficient for a 

 satisfactory determination. Ficus tiliczfolia Lx. has also been 

 found in the Laramie at Golden, Colorado, but its principal range 

 is in the Miocene and Pliocene. 



Corinis hyperborea was found by Lesquereux in California in 

 strata said to be Laramie, but the evidence seems insufficient 

 and the horizon is much more likely to be later. 



The Fort Union group is presented by no less than four spe- 

 cies, three of them belonging to the genus Viburmim, and one to 

 Ficus, while five species are found in the Green River group 

 (Eocene) with one species {^Salvinia Alkfii') heretofore entirely 

 confined to it. Two species have also been found in the Oligo- 

 cene. From this tentative review it is seen that all of the species 

 having a distribution outside of the auriferous gravels belong to 

 formations of Pliocene or older age ; none of them are more 

 recent or living. The number wholly or mainly Miocene con- 

 siderably exceeds the number found in any other ho.izon, and 

 none of the species are apparently confined to the Pliocene. 

 While the evidence is not yet sufficiently worked out to permit 

 a positive statement, it seems to point very clearly to the 

 Miocene Age of this deposit. 



The following is a list of fossil plants found at Independence 

 Hill. Quite a number are without doubt new to science, but as 

 they have never been published I have simply given the generic 

 name. 



Salvinia Alleni Lx. 



Arisamites n. sp. 



Ficiis sordida Lx. 



Ficus asiinincpfolia Lx. 



Ficus tilicefolia AL Br. 



Ficus sp. 



Ficus sp. 



Artocarpus Califorriica Kn. 



Ulmus Californica Lx. 



Ulmus officinis Lx. 



Ulmtis pseudo-fulva Lx. 



Ulmus n. sp.? 



Ulmus fruit of. 



Platanus appendiculata Lx. 



Juglans egregia Lx. 



Juglans sp.? 



Elicoria ? fruit. 



Salix Californica Lx. 



Populus Zaddachi Heer. 



Betula csgualis Lx. 



Be tula or Alnus, fruit. 



Quercus convexa Lx. 



