GEOLOGICAL SURVEY OF THE TEREITORIES. 419 



affinity is unkown as yet ; especially that from E vanston — G. aracMoides — 

 represented by bunches of fructification resembling the common pea-nut. 



The exposition of the general characters of our Tertiary flora, as indi- 

 cated by the nomenclature of a number of its species, is, however, far 

 less interesting and important than the documents furnished by the 

 table for definitively solving the question of the age of the formations 

 which the vegetable remains represent. I shall now use these documents 

 especially as a final summary of the arguments in favor of the assertion 

 that the Lignitic of the Eocky Mountains is, in its whole, an Eocene 

 formation. 



1st. No section is marked in the table for the comparative distribu- 

 tion of the Cretaceous flora, for the good reason that it represents the 

 same group of the Cretaceous, and that as yet not a single one of its 

 species is recognized as identical or even positively allied to any of our 

 Eocene. 



2d. The table has in the Eocene division a number of fucoids or ma- 

 rine plants, eight species; and, too, a proportionally large number of 

 palms, all vegetables, which are not only homologous or identical in 

 forms to fossil species of the European Eocene, but which, taken alto- 

 gether, constitute two groups characteristic of the Lower Tertiary, and 

 of which not a single representative, as yet, has been found in connec- 

 tion with a true Cretaceous formation. 



3d. The same may be said of some species marked in the same di- 

 vision ; one Fern, one Myrica, one Quercus, one Cassia, &c., identical 

 with species admitted in Europe as positively Eocene. 



4th. Of the species enumerated from the Eaton, Golden, Black Butte, 

 and Spring Caiion, a large number are allied to Eocene species, as, for 

 example, Ghinamomum affine, C. mississipiense, species of Fieus, of Ceano- 

 tJnis, J)o7nheyopsis, &c., and, considered in its essential groups, -FtcMS, Laii- 

 rus, Cinnamomum, Vihurnum, Cissus, Magnolia, Bomheyopsis, Sapindus, 

 EJianmus, Juglans, Cassia, &c., the whole flora bears a facies which, if 

 not positively comparable to that of the European Eocene, on account 

 of the scantiness of this flora, has, however, a marked analogy to that 

 of the Lower Miocene. As the characters, either separately, for a 

 number of species, or generally, in considering the facies of the groups, 

 are identical in all the strata which we have considered as Eocene, it is 

 evident that neither Black Butte nor any other locality can be separated 

 as from a different epoch, and that, therefore, no member of the Amer- 

 ican Lignitic, as far as this formation is known by its vegetable remains, 

 can be referred to the Cretaceous. An exception to this conclusion 

 is claimed for two localities, Bear Eiver and Coalville, wherefrom no 

 fossil remains of land-plants have as yet been obtained. But I do not 

 see how the separation could be made for strata which contain an 

 abundance of Eocene fucoidal remains, and whose thick deposits of lig- 

 nite indicate evidently, for the time, a laud formation of exactly the same 

 nature as that of the other localities. The lignite matter, indeed, by 

 its degree of decomposition, its chemical compounds, all its characters, 

 bears evidence of its origin by the same kind of land vegetation, and, 

 therefore, of its contemporaneity. On another side, the North Ameri- 

 can Eocene is considered by European paleontologists, from the char- 

 acter of its flora, as related to the Miocene formation. It is, therefore, 

 convenient to look further into the documents offered by the table in 

 regard to this last opinion. 



The proportion of species, of what is considered our Miocene flora, as 

 marked in the first three sections, is, with that of the Arctic, 11^ per 

 cent.; of the European Miocene, 39 per cent. Our Upper Eocene has 



