734 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



Cklastrus ellipticus n. sp. 

 PI. XCYII, fig. 3. 



Leaf of firm texture, nearly regularly elliptical in outline, abruptly 

 rounded above to an obtuse apex and below to an almost truncately rounded 

 base which is slightly decurrent along a short petiole; margin irregularly 

 sinuate-toothed from a short distance above the base; midrib rather thick, 

 passing straight to the apex; secondaries about 15 pairs, alternate or sub- 

 opposite, at an even angle of about 35°, straight; distal termination of 

 secondaries unknown; nervilles and finer nervation obsolete. 



This perfect leaf is 7 cm. long and 4.5 cm. broad. It is very slightly 

 unequal-sided, the difference being, however, hardly 3 mm. It is very regu- 

 larly elliptical, with a sinuate dentate margin, which begins about one-fourth 

 the length of the leaf from the base, the lower portion being entire. The 

 nervation is very regular, consisting of about 15 pairs of secondaries, which 

 emerge at an angle of about 35° and run straight toward the margin, but 

 the maimer of the termination at the margin can not be made out, from 

 lack of preservation. It is probable that they arch abruptly near the 

 margin and send secondary nervilles to the teeth. None of the nervilles or 

 finer nervation can be made out. 



It is possible that this species is closely related to C. incequalis, just 

 described, as they come from the same beds, but it seems hardly probable. 

 This latter species, as already pointed out, is very unequal-sided, with large 

 sinuate teeth, and peculiar arrangement of secondaries. C. ellipticus, on the 

 other hand, is almost regular in shape, has twice as man}' and smaller 

 sinuate teeth, and regular secondaries. 



This species does not approach closely to any described species of 

 Celastrus with which I am familiar. 



Habitat: Yellowstone River, one-half mile below the mouth of Elk 

 Creek, at base of bluff; collected by F. H. Knowlton, August, 1888. 



El^eodendron polymorphum Ward. 

 PI. XGVII, fig. 1. 



Elwodendron polymorphum Ward: Types of the Laramie Fl., p. 84, PL XXXVIII, 

 figs. 1-7. 



The fine specimen figured is referred with some doubt to this species. 

 It has much the same shape, serration, and type of nervation as E. poly- 



