DESCRIPTION OF SPECIES— BETULAL'E^. 141 



figs. 6-8, with borders doubly serrate, the teeth Ijeiiig small and sometimes 

 obsolete. This is the form recognized in the Miocene of Alaska, Greenland, 

 and the more common in Eur()i)e. The base of the leaves is rounded- 

 subcordate, the lower secondary nerves more or less branching The other 

 variety, a fragment of which is represented in pi. Lxiv, fig. 11, has the borders 

 either simply serrate or with a few irregular, large, more acute teeth ; all the 

 teeth, however, being larger and more obtuse than in the former variety. 

 The characters of the nervation are the same as seen in the figure ; the 

 leaves are obtusely pointed, not acuminate. By its larger obtuse teeth, the 

 leaf is more intimately related to Alnus nostratum, Ung., as described by 

 Ludw. (Palseont., p. 98, pi. xxxi, fig. 8). But this last species has the leaves 

 rounded at the top, and those of A. Kefersteinii, represented in Fl. Bait., 

 loc. cit., especially fig. 9, agree entirely, in their form and the denticulation 

 of the borders, with the fragment under consideration. 



Habitat. — Evanston, Wyoming; not rare The fragment represented 

 on pi. lxiv, near Florissant, Souti) Park, Colorado (Z)r. F. V. Hayden). Nine 

 miles southeast of Green River, "Wyoming {Win. Clehurn). 

 A.lnite8 iiisequilatcralis, Lesqz. 

 Plate LXII, Figs. 1-4. 

 Alnites inocquilateralis, Lesqx., Annaal Report, 1874, p. 307. 



Leavej rather thin, apparently membranaceous, very variable in size and form, broadly oval, 

 obtnse or obtusely acuminate, rounded to the short petiole, distantly crenato-serrate ; lateral nerves 

 curving to the borders, either entering the teeth by their ends, or passing under them to follow the 

 borders in simple festoons, joining the teeth by small branchlets. 



The leaves vary in size from four to eight centimeters long and from 

 three to six broad, one of the sides measuring generally one-fourth in width 

 more than the other. The irregularity in the number of the veins is corre- 

 spondingly great; one of the leaves, the smallest (fig. 4), for example, having- 

 six lateral veins on the left side, the lower much branched, while the other 

 side has ten, all simple. There are a number of fragmentary specimens of 

 the largest-sized leaves, like figs. 1 and 2, and these appear all related by 

 their outlines and the nervation to Populus Lebrunii, Wat., a species which 

 Saporta considers identical with his Alnus cardiojihylla, S(iz. Flor., p. 55, pi. iv, 

 fig. 9, and pi. xv, fig. 8. This last figure especially is much like fig. 1 of our 

 plate, merely diflfering by the form of the teeth, which, in the American 

 species, are broader and more obtuse. In this also the nervation is more 

 distinctly pennate, and the disposition of the veins to enter the teeth by their 



