DESCRIPTION OF SPECIES— SALTOINE^. 169 



the same locality has oiil}' one-half of a leaf, also of the same width, twelve 

 millimeters broad in the middle, showing the under part, with secondary 

 veins distinctly marked, like their divisions, and the snrface evidently villous, 

 or bearing the impression of a coating of hairs Prof Ileer, in his description 

 of this species, compares it to S.viminalis, Linn., a living and common species 

 of this country, remarking, however, that the s[)ecimens do not indicate 

 whether the leaves are villous, as in the living species. This villosity is not 

 apparent upon well-preserved specimens received from Oregon. 



Habitat. — Green River Station, Wyoming, above fish beds {Dr. F. V. 

 Hat/den). One fragmentary specimen from six miles above Spring Canon, 

 Montana, appears referable to the same species. 



Salix elougata, O. Web. 



Plate XXII, Pigs. 6, 7. 



Salix elongata, O. Wel>., Palaeont., vol. ii (Separ. Abdr.), p. 63, pi. ii, fig. 10. — Heer, Fl. Tert. Helv., ji, 



p. ;il, pi. Ixix, figs. 15, 16.— Lesqx., Auiiual Keport, 1872, p. 372. 

 Salix longisaima, W< as. & Web., Palaeont , iv (Separ. Ab<lr.), p. 30, pi. v, fig. 6. 



Leaves entire, long, lanceolate, gradually narrowed from the middle toward the point and toward 

 the petiole; middle nerve thin ; borders apparently revolute or reflexed ; secondary veins open, distant. 



The leaves of this species, at least judging from the fragmentary speci- 

 mens which I refer to it, are larger than those of the former, more distinctly 

 lanceolate and more rapidly tapering to the point, coriaceous, with the veins 

 more di.stant, irregular in their relative position, and with a very narrow 

 midrib. These fragments have the same characters of tbrm and nervation, 

 as far, at least, as this may be discerned, as the fine leaf described {loc. cit) 

 by the author of this species. The leaves figured by Heer as representing 

 it are, however, narrower, linear-lanceolate, of the same form as those of 

 Salix longa, Al. Br., but distinct by the narrow midrib. 



Habitat. — Elko Station, Nevada {Prof. S. W. Garman). 



POPULUS, Linn. 



Represented merely by more or less fragmentary leaves, as it is as yet 

 in our American fossil ilora, the genus may be characterized as follows: — 



Leaves of various forms; broadly ovate, round or lanceolate, generally 

 cordate or rounded at the base ; long-petioled ; with borders entire, crenulate 

 or dentate; palmately nerved from the top of the petiole or from a distance 

 above the border base. The prinuiry and secondary nerves are caniptodrome, 

 anastomosing outside of the bends with ncrvilles, either passing directly to 



