78 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



diminishing rapidly and irregularly branched and flexuous above, are 

 characters common to the leaves of all the willow-oaks. Some leaves of 

 the living Q. imbricaria would closely resemble these if fossilized in the 

 same manner. In the Lauracese with lanceolate leaves the nervation is 

 generally much more exact and regular than in the specimen before us, the 

 side nerves being generally curved gracefully and more or less uniformly 

 upward, their extremities anastomosing, or, more rarely, reaching the 

 margin. If the fine reticulation of the tertiary nerves was distinctly 

 visible there would perhaps be little difficulty in determining with a good 

 degree of certainty the generic relations of this fossil. In the oaks this 

 reticulation is very fine, the areola? of rather uniform size and quadrangular 

 or polygonal, about as broad as long. In the willows the meshes are 

 larger, more irregular, and more or less elongated. 



Formation and locality: Cretaceous (Dakota group). Blackbird Hill, 

 Nebraska. 



Quercus simplex Newb. 



PI. XLIII, fig. 6. 



Proc. IT. S. Nat. Mus., Vol. V (March 21, 1883), p. 505. 



"Leaves lanceolate, long-pointed, narrowed, and slightly rounded at 

 the base; margins entire; nervation fine and regular." 



In collections made by Rev. Thomas Condon at Bridge Creek, Oregon, 

 are numerous leaves similar to that described above. Some are larger, but 

 all present the same characters. The form of the leaf is similar to that of 

 Q. consimilis, with which it is associated and from which it differs only by its 

 entire margin. Since in that species the margins are sometimes nearly 

 entire, it is possible that in the leaves before us that character may be 

 intensified, giving an entire variety. Of this, however, proof can only be 

 obtained by further collections. 



Formation and locality: Tertiary (Miocene). Bridge Creek, Oregon. 



Quercus sinuata Newb. 

 PI. XIII, fig. 1. 

 Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 27. 



"Leaves small, obovate in general outline, narrowed to the petiole, or 

 slightly decurrent ; margins deeply lobed, lobes rounded, broader than the 



