AGE OF TLIE LKJNITIC DETEIJMINED BY ITS FLORA. 331 



is iil)iiii(laii( at Florissant, f'ourlli groni). P/nagmites should pcrliaps be, as a 

 gmiiis, crnn'matcd iVoiii the niiinhcr ot' local rcprescntalives on account of" the 

 uncertainty of the dcterniination ot'tlic fragments; for, according to what has 

 IxH'n reniarlvcd in the description of the specimens referred to P. CEuiugois'is, 

 they may be referable to divers generic types. Hence the distribution of 

 these fragments in most of the groups cannot be depended upon as evidence 

 of relation of age. TIi(> same might be said of A'onts branc/iy.sf<///i//s, found 

 at lilack Buttes in poor spccinuMis, their ideiitilication with those of Carbon 

 and Florissant being d()ul)lful. 'I'licn w(; hiwe. Flahcllaria /^inkciii \\\ (•omnion 

 at Golden and iJarrell's Springs. From the remark added to tiie descrip- 

 tion of the species, it is seen that the relation ol" the Iragments Irom iiarrell's 

 Springs is not ascertained, no more than the reference of the locality to the 

 third group. Then we have Populus mutnhllls, which prevails in two localiti(;s 

 of tlie lower group,aud is also fijund at Evanston ; Ficus uncata, described from 

 specimens of the Eaton Mountains, Golden, and Carbon, or from the fir.st and 

 third groups; Ficus tilicefoHa, an omnipresent species, most coninion in the 

 European Miocene, and with us seen at nearly all the localities of the 

 Lower Lignitic, and also at Evanston in the Washakie group, and even 

 in the Pliocene of California. (Aiiixunoiiium affine also, which, common 

 in the Lower Lignitic, has been tbund at Carbon; Cissus i)arrotiafotia, a 

 rare species, seen at Marshall's, Mount Brosse, and the Lower Green River 

 group; Cistius lobato-crenata, found at Black Buttes and Mount Brosse; 

 Rhamnus rectinervis, common in the Miocene of Europe, as also in the 

 Lower American Lignitic, seen at Evanston; and then Juglans Leconkana 

 and J. riigosa, two species which relate to or perhaps represent the most 

 common ./. acuminata of the European Miocene, and which, rarely tbund at 

 Evanston, abound in diilerent localities of the first groups. Quoting still a 

 small fruit, Carpites glumaceus, obtained from Black Buttes and Evanston, 

 we have, as indicated in the table of these two hundred species of the Lower 

 Lignitic, sixteen only which pass into, or have been recognized in higher 

 groups of the Tertiary. This shows a unity and isolation of the Lower 

 Lignitic the more remarkable that none of its essential types, the Palms, 

 Magnolias, Grewiopsis, Viburnum, Rhamnus, etc., have, at least from what 

 is known now, passed abov(! it. 



The second group, that of J'.vanslon, has a pecidiar llora, and thus an 

 indefinite relation, either in regard to the other divisions, or to the different 



