26 DESCRIPTION OF SPECIES. 



FILICES. 



SPHENOPTERIS, Brgt. 

 Splienopteris corrugrata, Newby. 



"Later Ext. FI. of North America," p. 10; "Illustr.," pi. ii, fig. 6. 



Frond unknown; i)innu]es ovate or cuneiform, narrowed at the base, obtuse, 

 lobed, and often plicate lougitudinally; nerves distinct, dichotomous, branching from 

 the ba.se. — (Newby.) 



HYMENOPHYLLUM, Klf, 

 Hyiueuopbylluin cretaceum, Lesqx. 

 "U. S. Geol. Rep.," vi, p. 45, pi. i, figs. 3-44; xxix, fig. 6. 



In describing this species I related it to the preceding from the 

 description given by the author, as I had not then seen the figures. These 

 indicate a degree of relation which cannot be positively ascertained on 

 account of the too fragmentary specimens. The fronds were evidently 

 large in the plants of this kind. The divisions are multiple and extremely 

 variable. The specimens may, therefore, represent pinnules derived from 

 divers parts of fronds of the same species. 



PECOPTERIS, Brgt. 

 Pecoptcris Nebraskana, Heer. 



"U. S. Geol. Rep.," Ti, p. 46, pi. xxix, figs. 5, 5<i. 



GLEICHENIA, Sw. 

 Gleicheiiia Kurriana, Heer. 

 "U. S. Geol. Rep.," vi, p. 47, pi. i, figs. 5-5c 



Gle'icheuia NordenskiOldi, Heer. 



Pl.ite I, Figs. 1, la. 

 Haydeii's •'Ann. Rep.," 1874, p. 334, pi. ii, fig. 5. 



5"rouds slender, bi-polypinnate; idtimate pinnae alternate, rigid, open, linear, 

 parallel; pinnules subcoriaceous, small, free, oblong-ovate, obtuse, rounded at base on 

 both sides, inclined upward; secondary veius few, three or four pairs, the lower forking, 

 the upper simple. 



Though the American specimens of this species are small they show 

 distinctly the essential characters of the species: the slender rachis of the 

 ultimate pinnae rendered flexuous by compression of the basilar border of 

 the pinnules, the very small leaflets free and rounded at base, and the 

 disposition of the veins. The specimens which I have for examination 

 are sterile. As seen and figured by Prof. Heer, the fructifications are those 



