290 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



V. Haydcn's collection indicate leaflets of still larger size. The substance 

 of these leaflets is subcoriaceoiis and rigid, the surface generally polished, 

 though deeply cut by numerous lateral nerves and nervilles ; the borders, 

 crenulate or denticulate, become entire toward the more or less inequi- 

 lateral base, of which one side is generally rounded, the other straight, The 

 petiole of the lateral leaflets is short; that of the terminal ones longer, as 

 represented in fig. 2. The lateral nerves are close, twenty to twenty-five 

 pairs in the large leaflets, under a broad angle of divergence, 50° to 60°, 

 mostly simple, closely following the borders in simple bows, connected with 

 the teeth by minute short nervilles. Though this species has been ably and 

 distinctly described by Prof. Newberry, the abundant materials which I have 

 at hand, representing its leaflets in their diversified size and shape, have 

 induced me to give figures of those which show its more marked char- 

 acters. The generic relation of the species cannot be definitely considered 

 as long as the fruit is not known. As the North American species o{ Juglavs 

 and Carya can be used only as points of comparison by the characters of their 

 leaves, these characters, especially the generally simple secondary nerves in 

 our species of Juglans, more generally divided in those of Carya, seem to 

 refer this fine species, whose lateral nerves are not at all divided, to the first 

 genus. The size of the leaflets, however, has more likeness to those of 

 Carya alba, though all the fossil leaflets of Carya published by European 

 authors are narrow and linear, and also the branching of the nerves is quite 

 as distinct in Juglans riipestris as in the species of Carya. 



Habitat. — Evanston, Wyoming, below the main coal {Dr. F. V. Haydm). 

 It is there abundant, and I have obtained it in very fine specimens, but have 

 not seen it anywhere else. 



PTEROCARYA, Kunth. 

 Pterocarya Americana, Lesqz. 



Plate LVIII, Fig. 3. 



Pterocarya Americana, Leaqx., Aunual Report, 1873, p. 417. 



Leaflets oblong, apparently lanceolate upward, and narrowed to the base; lateral nerves more 

 open toward the base, parallel, ineqaidistant, slightly curved. 



The lateral nerves are more distant and more irregularly distributed than 

 in species of Carya, and also the arches do not reach quite as near the borders. 

 I compared this species {loc. cit.) \o Pterocarya Massalongi, Gaud. (Contr., i, 

 p. 40, pi. ix, fig. 2), the form of the leaflets, their nervation, and border divis- 



