FOSSIL FLORA. 743 



seemingly craspedodrome, occasionally branching near the margin; finer 

 nervation not preserved. 



The specimen figured is the only one that has been found. It is 14 

 cm. long without the petiole, which is 4.5 cm. in length. Both sides of the 

 leaf are destroyed, but it was probably about 10 cm. wide. 



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

 bluff about 40 feet above the river ; collected by F. H. Knowlton, August 

 27, 1888. 



TILIACEiE. 



TlLIA POPULIFOLIA Lx. 



Tilia populifolia Lx.: Oret. aud Tert, PL, p. 179, PI. XXXIV, figs. S, 0. 



A single large, fairly well preserved specimen is all that has been 

 found of this species It is referred with very little doubt to Lesquereux's 

 species, which was before known only from Florissant, Colorado. It is a 

 little less heart-shaped at base than fig. 8 (loc. cit.) of Lesquereux's plate, 

 but in the discussion of this species Lesquereux describes it as "round or 

 subcordate at base." The teeth are of precisely the same character, being- 

 only slightly smaller. The thick petiole and fine palmate nervation are 

 identical, as is the other secondary nervation. 



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

 Creek, top of bluff; collected by F. H. Knowlton, August 27, 1888. 



GrREWIOPSIS 1 ALDERSONI 11. sp. 



Leaves of firm texture, broadly obovate, truncate or slightly heart- 

 shaped at base, obtusely acuminate above; margin entire at base, slightly 

 undulate-toothed above; midrib thick, straight; nervation pinnate; second- 

 aries about 6 pairs, alternate, at an angle of 45°, camptodrome; lowest 

 pair subopposite, arising some distance above the base of the blade, with 

 3 or 4 tertiary branches from the outside which are camptodrome and 

 arch well inside the margin; upper secondaries occasionally forked near 

 the margin; nervilles strong, percurrent. 



I refer several specimens to this somewhat doubtful species. Neither 

 of them are perfect, but as far as can lie made out the average length 

 appears to have been about 9 cm. and the width about 6 cm. 



It is doubtful if these leaves belong to the genus Grewiopsis, but at 



