with Description* of X w Speci< 8 of /' ssil Pla 



lateral nerves are much less uniform and regular than thosi 

 the leaves to which I have referred. They are at first str< 

 but soon diminish, and many of them extend bill halfway to 

 the margin ; the others being unequally curved and branching 

 irregularly, or anastomosing with each other. The finer details 

 of nervation are not given in the specimens before me, and 

 perhaps more ample material will show that our fossil Bhould 

 not be regarded as a Quercus, but as far as its characters are 

 given, they agree best with those of that genus. The texture 

 of the leaf was evidently thick, and its surface glossy, raor< 

 than in any Salix now living ; the nervation, t<>,». is more that 

 of the oaks than willows ; the alternation oflarger with smaller 

 secondary nerves, all diminishing rapidly and irregularly 

 branched and flexuous above, are characters common t<> tin- 

 leaves of all the willow-oaks. Some leaves of tin- living 

 imbricaria would closely resemble these it" i'"--i!ixrd in tin- 

 same manner. In the Lauracett; with lanceolate leaves tin- 

 nervation is generally much more exact and regular thai 

 the specimen before us, the side nerves being generally curved 

 gracefully and more or less uniformly upward, their extremil 

 anastomosing, or, more rarely, reaching tin- margin. If tin- fine 

 reticulation of the tertiary nerves was distinctly visible, there 

 would perhaps belittle difficulty in determining with 

 degree of certainty the generic relations of thi I. In the 



oaks this reticulation is very fine, the areolae of pretty uniform 

 size and quadrangular or polygonal, aboul a- broad as lc 

 In the willows the meshes are larger, more irregular and m 

 or less elongated. 



Formation and Locality. Lower Cretaci 

 Blackbird Hill, Nebraska. (Dr. Hayden.) 



QiiercBi* ciineata. (n. p.) 



Leaves short petioled, lane olate, pointed 

 entire or slightly wave-margined; midrib stroi 

 remote, nearly straight, with shorter into 



smooth, texture originally thick ami Ieath< 



