696 GEULOGY OF THE YELLOWSTONE NATIONAL PAKK. 



Habitat: Yellowstone River, one-halt' mile l)elow the mouth of Elk 

 Creek, top of bluft"; collected bj- F. H. Knowlton, August, 1888. 



POPULUS DAPHNOGENOIDES "Ward. 

 PI. LXXXIV, tig. -'. 

 Popidns daphnogenoides Ward: Types of the Laramie FL, p. 20, PI. VII, figs. 4-6. 



The collection contains some 20 specimens that are referred to this 

 species. They have the same general character, but are a little larger, 

 with a more prolonged point and rather stronger nervation. There are no 

 essential diffei-en^-es, however. 



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

 Creek, top of lilutf; collected by F. H. Knowlton, August, ls8H. 



POPULI'S P.ALSAMOIDES Gopp. 

 PL LXXXYI, lijj. 1. 

 ropuJus halsamoldes Gopp. Lesqueieux : Cret. aud Tert. Fl.. p. 24S, I'l. LY, figs. 3-5. 

 The fragment tigured is the only specimen of this species detected. 

 It represents the basal ])ortion of a medium-sized leaf, and agrees satisfac- 

 torily with the tigures of this species as given b}' Lesquereux. 



Habitat: Cliff west of Fossil Forest Ridge; collected l)y Ward and 

 Knowlton, Angust Ih, IXS". 



PoPULUS ? VIVARIA n. Sp. 

 PI. LXXXYI, tig. 2. 



Leaf thick, roundish, or Ijroadly elliptical in outline, toothed to near the 

 base; teeth large, acute; nervation pinnate, camptodrome, or imperfectly 

 craspedodrome ; secondaries strong, opposite or suljopposite, emerging at 

 various angles, forking near the margin, the branches arching into bows 

 and apparently sending branches from the outside to the teeth: nervilles 

 obscure, but a]iparently percurrent. 



This doubtful species rests on the single fragment figured. It was 

 apparently about 10 cm. long and 7 cm. wide. It has some resemblance to 

 certain species of Populus from the Fort Union group of the lower Yellow- 

 stone, as, for example, I', f/reiriojisis Ward,' but differs in the branching of 



'Types of the Laramie Fl., p. 23, PI. IX, fig. 1. 



