24 Later Extinct Floras of North Amei 



lized, but in the fossil plant the lateral nerves are sharply de- 

 fined, numerous, aluao6t perfectly parallel among themselves 

 and run quite to the margins, which arc seen to be slightly 

 waved, the termini of the nerves being most prominent and 

 the intervals between them forming shallow sinuses. In 

 R/iamnus, however, even in R.frangula y of which the leaves 

 nucb resemble this, the margins are not waved, and the 

 lateral nerv< e do nol terminate as distinctly in them as they do 

 in Fagus, and in our fossil. 



A striking similarity will be noticed between some of the 

 leaves of the living Fagus sylvatica and this, though there is no 

 probability of thai species having begun its life so early in the 

 history of the globeas the first part of the Cretaceous period. 

 The resemblance is noted only as giving good grounds for the 

 n nee of the fossil to the genus Fagus. It will be necessary 

 however to find the fruit before the fact can be accepted as 

 fully proven of the existence of beeches during the age of the 

 Chalk. 



A large number of fossil species of Fagus have been i\v- 

 scribed from the Tertiaries of Europe, by Unger, Dunker, 

 Beer, &c, bnl the genus has never before been obtained from 

 the Cretaceous formation. 



Formation and Locality. Lower Cretaceous sandstones, 

 Smoky Hill, Kansas. (Dr. Hayden.) 



(liu'iM'ii* salirilolin. (n. sp.) 



Li ■ ■ - petiolate, Bmooth, thick, entire, lanceolate, abruptly 

 pointed at both ends ; medial nerve stro ht, or more or less 



curved; secondary nerves of unequal size, strong near their points 

 of origin, becoming fine, flexuous and branching as the} approach 

 the margins of t In- leaf, where some of them inosculate by irregular 

 curves, while others terminate in the margins. 



This Bpecies differs considerably in its general aspect fr< 



the willow-like leaves with which it is associated, and must 



have been much thicker and smoother. The midrib is verj 



, terminating below in a thick hut Bhorl petiole. The 



