710 GEOLOGY OF THE YELLOWSTONE NATIONAL TAEK. 



apparently rather aljrnjitly i)ointed. Thu teetli are strong and sharp-pointed, 

 Avith rounded sinuses. 



This species seems to be allied to (J. hou-cniana Lx.,^ from California, but 

 differs essentially in having nuich larger, sharper teeth and straight 

 secondaries. It is also allie<l to <^). i/tii/rt'i/i which has midulate or slightly 

 toothed margin and fewer, more curved secondaries. It somewhat 

 resembles a leaf that has been described as Hicoria culver i, which, however, 

 differs in the teeth, and in having a camptodrome instead of a craspedodrome 

 nervation. 



Habitat: Yellowstone River, one-half mile l)elow mouth of Elk Creek, 

 at top of buiff; collected l)y F. H. Knowlton, August, 1888. 



Dryopyllum longipetiolatum n. sp. 

 PL LXXXVIII, figs. (5, 7. 



Leaves lanceolate, long wedge-shaped at base, long narrowly acuminate 

 at apex, margin regulaidv undulate-toothed, the teeth sharp, upward point- 

 ing, separated by rather shallow sinuses ; petiole very long, slender ; midrib 

 thick, straight; secondaries numerous, alternate, 12 pairs or more, at a low 

 angle in the lower part, more acute above, slightly curving outward in 

 l^assing to the margin, all ending in the teeth ; nervilles at right angles to 

 the secondaries, obscure l)ut apparently mainly itercurrent ; liner nervation 

 destroyed. 



This species is represented by a number of specimens, none of which 

 are complete in a single example, but by combining several a good idea of 

 the species is given. The length appears to have been about 20 cm. and 

 the width in the middle 4 cm. The petiole is long, being 2.5 cm., and pos- 

 sibly not all preserved. In the larger leaves the secondaries are quite 

 remote and distinctly alternate. They arch slightly in passing to the teeth. 



The leaves of this species w^ere at first confounded with leaves of 

 Castanca pulclieJla, with which they occur in the same beds, but they differ 

 in the longer petiole, the smaller teeth, anil in the irregular, arching 

 secondaries, with an occasional intermediate secondary between. The 

 teeth of the upper tliird of the leaf are also of a different character. 



' Mem. Mus. Comp. Zocil., Vol. VI, No. 2, p. 6, PI. II, figs. 5, 6. 



