LESQUEREUx.] PALEONTOLOGY— LIGNITIC FLORA AGE. 377 



at least, represent types of the Upper Miocene only. Among species of 

 tlie other genera of Eocene type, the Liguitic iiora has still Myrica Torreyi 

 of Blacb-Butte, possibly identical, as seen above, with a Lomatia of Mount 

 Bolca ; three species of Platanus : P. Raydenii, P. liaynoldsi, P. rliom- 

 hoides, without any aifiuity with any of the Cretaceous or of the Miocene 

 species known as yet ; Artocarindkmi olmediccfolhim, U., described by 

 the author from Sotzka ; a fine new species of Pisonia, P. racemosa, 

 allied to P. eocenica, Ett., of Haring, as well by the seed (or unopened 

 buds) as by the leaves ; Daplinogene anglica (?), which has been remarked 

 upon as found at Alumbay ; two species of NeluviMum, related to JSf. 

 BucM, Ett., of Promina; Piicalyptits Hdringiana, of Haring; Bombey- 

 opsis grandifolia, U., of Sotzka; a number of species of liluwinus of a 

 peculiar type, comparable, by the form of the leaves and the nervation, 

 to tropical species of Bridelia. These can be considered as already 

 giving to the flora of the Lignitic, in comparing it to that of Europe, an 

 Eocene facies. 



But we have in America a more reliable point of comparison, still. 

 forcing the conclusion that if even the Lignitic flora of the Eocky Mount- 

 ains had no relation whatever to that of Europe, it should, notwith- 

 standing, be considered as Eocene. I allude to the flora of the Missis- 

 sippi, described from very good specimens obtained from such a lower 

 stratum in the Tertiary that its reference to this formation rather than 

 to the Cretaceous was for a long time uncertain. In the Geological Ee- 

 port of the State of Mississippi, Prof. Eug. Y. Hilgard has given (p. 108) 

 a section of the general distribution of the strata in the geological for- 

 mations of the State, marking the place of the Lignitic of the Missis- 

 sippi State and of the formations where his fossil plants were found as 

 underlying the Vickshurgh and Clayborne beds, which form the ui)per 

 stage of the American Eocene, the Lignitic representing the lower one: 

 The correlation of the Mississippi fossil flora with that of Golden and 

 of Black 'Butte is evident enough. Of the Mississippi plants, the fol- 

 lowing have been recognized in the Western Lignitic: Siibal Graya7ia, 

 Yaucouver ; Pojnilus monodon, Eaton Mountains ; P. mutabilis. Black 

 Butte, Eaton Mountains, Yancouver; Quercus cliloropliylla^ Golden; 

 Quercus crassinervis, Yancouver ; Ficus ScMmjperi, intimately related to 

 F.platlnervis, as widely represented at Black Butte, Golden, &c., as the 

 former is in the South ; Lmirus pedata, Eaton Mountains ; Cinnamomum 

 Mississippiense, one of the most prevalent species of the Western Lig- 

 nitic ; Magnolia Hilgardiana., Eaton Mountains ; M. Lesleyana, Eaton 

 and Golden. This, without mentioning a number of closely-allied spe- 

 cies and the identity of genera, gives to both the floras of the IMississippi 

 and of the Western Liguitic formation a general character which can but 

 be recognized as identical. 



After all this, we remark in our Eocene flora some characters which 

 may be called negative, namely, the absence of certain groups of plants 

 represented either in the Cretaceous or in the upper groups of the 

 Tertiary. Ko species has been discovered in the Lignitic which had 

 been described from the Dakota group. This is the more remarkable 

 that sonie peculiar types of this group, like Liriodendron, Sassafras, 

 &c., re-appear above the Lignitic in the Evauston or second group, 

 and in still greater numbers in more recent Tertiary divisions; and 

 that even one of its rare species, Cinnamomum Scheuchzeri, is also 

 absent until now, at least in the lower group, and present in the 

 same second group and above. Heer remarks, in considering the fossil 

 flora of Mount Bolea, the absence of representatives of a number of 

 genera or families which take an important place in the Miocene, thus : 

 Salicinecc, Acerincw, Cupuliferw^ Betulacew, Ulmacecv, J^Mctinece, &c. 



