52 UJJITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



at with a strong glass, the surface appears minutely punctulate, as if it had 

 been covered by a kind of soft villosity. 



By the shape of its pinnules, decurrent upon the rachis, their divisions 

 and nervation, this Fern evidently resembles some of the living species of 

 Hymenophyllum. But it is as yet too indistinctly represented to offer posi- 

 tive points of comparison. 



Habitat. — Golden, same place as the former species. 



PTERIS, L. 



Ptcris pseudopennseformis, Lesqz. 



Plate IV, Figs. 3, 4. 



PterU pennaformis, Heer, Fl. Tert. Helv., p. 38, pi. xii, fig. 1. — Lesqx., Annual Report, 1873, p. 392. 



Pinnae linear-lanceolate, gradually narrowed upward, entire to above the middle, obtusely den- 

 tate at and near the point, subcoriaceous ; middle nerve thick, bi-grooved, and three-striated toward the 

 base ; veins in an acute angle of divergence, close, thin, mostly simple or forking once. 



The fragments representing this species, and of which the best ones have 

 been figured, seem referable to the Miocene form described by Heer. The form 

 of the leaflets is the same ; they are also crenulate-dentate toward the point, and 

 the veins, at the same acute angle of divergence, are, as in the European spe- 

 cies, either simple or forking once. There is, however, a difference in the 

 more obtuse denticulations, which the author describes as somewhat sharp 

 {ziemlich scJiarf), and especially in the veins, which appear more numerous 

 and close in the American form. 



A comparison of specimens only could determine either identity or a spe- 

 cific difference between the European and American forms. 



Habitat. — Henry's Fork (Dr. F. V. Hayden). 



Ptcris subsimplcx, Lesqz. 



Plate IV, Figs. 5-7. 



Pieris auisimplex, Lesqx., Annual Report, 1873, p. 392. 



Fronds or pinnee coriaceous, large, entire or minutely crenulate, ovate-lanceolate, gradually nar- 

 rowed in a curve to the base ; middle nerve narrow, deep ; veins at an open angle of divergence, dis- 

 tinct and distant, simple, or merely forking once near their base or toward the middle. 



The fragments of this Fern represent either simple fronds or some sepa- 

 rate pinnae of a large frond. They are ovate-lanceolate, tapering gradually 

 to a point (broken), and narrowed in a curve to the base. As seen in fig. 6, 

 the fragment is slightly uncquilateral at its base, and thus resembles a pinna 

 rather than a frond ; the part in fig. 5 also is different in shape and size, as 



