290 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



V. Ilaydt'ii's collection indicate leaflets of still larger size. Tlie substance 

 of tliese leaflets is subcoriaceous and rigid, the surlace generally polished, 

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

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

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

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

 represented in fig. 2. Tlie 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 of Jug Ian s 

 and Canja 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 Juglam, more generally divided in those of Carya, seem to 

 refer this fine i^pecies, 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 rupestris as in the species of Carya, 



Habitat. — Evanston, Wyoming, below the main coal {Vr. F. V. Hayden). 

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

 not seen it anywhere else. 



PTEROCARYA, Kunth. 

 Picro carya Americana, Lesq:s. 

 Plate LVIII, Fig. 3. 

 Pterocarya Americana, Lesqx., Annual Report, 1873, p. 417. 



LcalletH oblong, apparently lancool.ato upward, and narrowed to tlio base; lateral nerves more 

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



The lateral nerves are more distant and more irregularly distributed tlian 

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

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

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



