No. 517] 



MIOCENE TREES 



refers here, all from Fossil Forest Ridge. This 

 is, undoubtedly, a distinctively Miocene plant, 

 and must be accepted as pertinent evidence. 

 The determination must be presumed to be 

 correct, though it may be pointed out that 

 various other leaves have almost exactly 

 the same venation and appearance. This is 

 especially true of the species of Zeikova, to 

 which genus Engler (18D4) actually referred 

 F. longifolia, though the discovery of the fruit 

 has since shown that it is not related thereto. 

 Ulmus plurinervia, as figured by Heer from 

 Alaska, is also almost exactly like F. longifolia; 

 it is considered doubtfully Eocene, but Knowl- 

 ton has recognized it in the Mascall (Miocene). 

 From the shape of the base, and other features, 

 it seems to me certain that the Alaskan plant is 

 not the original U. plurinervia, of which linger 

 gives four figures in the Ohloris Protogsea. The 

 latter is decidedly more elm-like in appearance. 

 Corylus macquarrii (Forbes) Heer. This plant, 



None of the above belong to the genuine Green River 

 series; three are quite without significance as indicating- 

 Miocene affinities, but the Fag its stands out as a solitary 

 Miocene representative. 



7. Common to the Lamar and the Auriferous gravels 

 of California. (See also under 1 and 3.) 



Juglans leonis Ckll. Two specimens in the Lamar. 

 Populus balsamoides Gopp. Also Miocene (?) of 

 Alaska. Known in the Yellowstone only from 

 a fragment, which certainly can not be positively 

 determined as balsamoides: in fact, it shows 



