62 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



clifTering greatly, however, by the broader divisions, and the nervation, which 

 is of a far different type. Indeed, I do not know any species of this genus, 

 either fossil or living, whose secondary veins are so close and as many times 

 forking, resembling, by this character, species of Neuropteris of the Carbon- 

 iferous age. The consistence of the leaves is somewhat thick. 



Habitat. — Barrell's Springs, Washakie group {Dr. F. V. Hayden). I 

 have not visited the locality and I mark the geological reference of this spe- 

 cies as it is indicated upon the labels of the specimens sent to me already in 

 1870, Most of these specimens have leaflets and rhizomas only of the same 

 Lysodium. The others bear, besides this species, fragments of Palm rays 

 and of Equisetum Haydenii. The fragments of Palms have double, compara- 

 tively broad (four centimeters), distinctly veined rays, the primary veins at very 

 irregular distances, the secondary ones extremely thin, a kind of nervation 

 similar to that of Flahellarla Zinkeni or of Sabal communis, two species 

 described in the following pages. These fragments are undeterminable, 

 but merit to be mentioned on account of the geological references. As 

 yet, species of Palms have been found in Colorado and Wyoming, only 

 with the Lignitic No. 1. But though they are positively considered as 

 characteristic of the Lower Lignitic, or Lower Eocene, in its separation from 

 the Cretaceous, they may be found in the upper stages. A Sabal, for 

 example, is, in good specimens, with the plants of the Upper Tertiary, or 

 Pliocene, of California. In this case, however, and in the presence of a 

 Fern, type of a subtropical climate, we see a discrepancy in the climatic cir- 

 cumstances indicated by the other species considered as belonging to the 

 same geological horizon. No. 4, whose vegetable forms represent a more tem- 

 perate zone. It is therefore advisable to consider the reference of this 

 locality to the Washakie group as uncertain until we have more reliable docu- 

 ments in regard to its geological station. The fragments from the same locality, 

 referred to Cyperus Deucalionis, }ieer, in Rep., 1870, p. 384, though compara- 

 ble to the species by their nervation, are too obscure to merit consideration. 



L. y g o d i 11 m M a r v i n c i , Lesqz. 



Plato V, Fig. 8. 



Lygodium Marvinei, Lesqx., Anuu.-vl Report, 1874, p. 309. 



Leaflets tripartite?; divisions oblong, narrowed to a point, serrulate toward the point; middle 

 vein thin, very distinct ; secondary veins twice forked. 



We have only the fragment figured here, too incomplete to give a good 



