332 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



localities ascriijed to it. It is, moreover, insufficiently known; for it is 

 represented until now by only thirty-four species, twenty of wliicli are 

 limited in their range to this division. Of the other, Taxodlum disticlium 

 miocenicum is at Fort Fetterinan and Elko. Populus arctica, of the Miocene 

 Arctic flora, abundant at Carbon, found at Green River, is also of frequent 

 occurrence in the Miocene of Alaska. With the third group, that of Evanston 

 lias still in common Bctula Steve?isoni, Alnus Kefersteinii, Populus subro- 

 tundata, and Ficus tilicefolia, all species, like the former ones, of Miocene 

 type, as well as Rhus Einnsii, which it has in common with the Ui)per Green 

 River group. With the lower group, its relation is merely liy Populus 

 mutabiUs, Ficus tilicefolia, Cissus lobato-crenata^ Rhamnus rectinervis?, Juglans 

 rugosa, and J. Leconteana, already remarked upon, with four species of 

 Carpites or fruits, whose relation of age is too indefinite to be taken into 

 account. The amount of affinity with the first group is, therefore, by the 

 count of species, about the same as with the upper divisions; but those 

 relating it to the lower one are, like the other forms, of Miocene type, even 

 Cissus lobato-crenata, whose affinity is witii a species of the Union group, 

 and with G. tricuspidata of Alaska. Hence the correlation of age, as far as 

 it can be recognized, is with the upper group, mostly with the Miocene. 

 The vegetable types peculiar to this second division are especially Lau- 

 rinece, represented by five species, while the whole Tertiary flora of the 

 Lignitic has until now only seven, the two others pertaining to the lower 

 group. These five species have a distinct affinity with European Lower Mio- 

 cene types, as well as Betula Gaepperti^ Cornus impressa, Cassia concinna, while 

 Cimiamomuyn lanceolafum, Diospyros JVodani, Vitis Olriki, Cornus Studeri, 

 are true European Miocene species. Hence the relation of the group tends 

 upward. Its Amlia gracilis and A. notata have the same degree of 

 relation to Cretaceous types of Nebraska as to Pliocene species of Califor- 

 nia, and Quercus negundoides, Rhamnus iniermedius, and Carya antiquorum 

 have no distinctly marked relation to other fossil plants described until 

 now. Therefore, the general character of the plants is Miocene, scarcely 

 modified by a few forms passing to the lower divisions. I find, however, no 

 sufficient reason to unite it to Carbon, from which some of its es.sential 

 types differ, and it cannot be certainly united to the lower group of the 

 Tertiary, of which it has not one of the essential Eocene characteristic spe- 

 cies. This small flora seems to represent a peculiar stage intermediate between 



