26 Later Extinct Floras of North Ameri 



The leaves of this species musl liave been similar in form 

 and consistence to those of the living Q. imbricaria. They 

 were somewhat longer-pointed, and slightly more cuneate 

 at the base ; bnl leaves might be selected from the living tree 

 which, if fossilized in the same manner, would be scarcely 

 distinguishable from those before us. The nervation is strong, 

 the primary and secondary nerves being very distinctly marked, 

 the latter remote, straight the greater part of their length, 

 gently curved inward their extremities. 



Oaks would seem to have been numerous in the oldesl forests 

 of dicotyledonous i rees of which we have any knowledge. Sev- 

 eral species are enumerated by Stiehler as occurring in the Creta- 

 ceous sandstones of Blankenburg, but they are as yet nol de- 

 scribed; and in the tertiary flora of Europe, perhaps no genus 

 is more largely represented. 



( >n our own continent oaks were apparently common as early 

 as the epoch of the deposition of the Lower Cretaceous strata, 

 as leaves, which I have considered referable to Qu reus, are 

 included in most of the collections which 1 have made from 

 se strata from widely separated localities, vi/.: Bellingham 

 Bay, Kansas, Nebraska, Utah and New Mexico. 



Formation and Locality. Blackbird Hill, Nebraska. (Dr. 

 Hayden.) 



Quercu§ n9itirgua. (n. sp.) 



Leaves of medium size, lanceolate in outline, aoute, often Bome- 



wliai flexuous; margins serrate-dentate, with strong, obtuse teeth, 



which are appressed or turned toward the Bummit ; midrib strong, 



and reaching the apex; lateral nerves numerous, of unequal 



"tli, rjentlv arched upward, terminating in the marginal teeth. 



The specimens upon which this description i ! are I 



silized in r Bomcwhat coarse ferruginous Bandstone, which has 

 not presen ed the minor details of the nervation ; but the gen- 

 eralities of form and structure, which arc clearly enough shown, 

 in to indicate that it represented in the Cretaceous flora the 

 chestnut-oaks of the present epoch. Several Tertiary Bpeciee 



