with Descriptions of New Sp< eu a of Fossil Pla 7 1 



tations on either side, while in P. Haydenii the man,: 

 has 8-10 teeth on eacli side of the middle lobe. The difference 

 before specified in the form of the marginal teeth ie vorj 

 marked and strikes the"eye at a glance. In /'. </<■, roiddt they 

 are few, long and acnte, sometimes even uncinate, while in /'. 

 Haydenii they are more numerous, loss prominent and always 

 obtuse, sometimes merely giving a wavy outline to tin- margin 

 of the leaf. 



Detached seeds are all that we have of the fruit, and tie 

 though plainly derived from a Platanus, in their condition of 

 fossilization, afford no good characters with which to compare 

 this species with the two now living "ii this continent, or with 

 the living and fossil species of the Old World. 



P. aceroides, according to Ileer, had fruit in racemes like 

 the Mexican plane tree, while, as every one knows, the fruit of 

 P. occidentcdis is single. In general aspect, the Bpeciee now 

 before us is more like the Eastern than the Western ofour 

 American sycamores, to the former of which it has considera- 

 ble likeness, and may very well have been its progenitor. 



Formation and Locality. Miocene strata. Banks of the 

 Yellowstone Eiver. (Dr. Hayden.) 



Cornus acuminata, (n. Bp.) 



Leaves ovate or ovate-lanceolate, long-pointed, acute, entire, nar 

 rowed at the base and slightly decurrenl ; midrib distin* ' 

 or curved toward the summit, following the course of the fr< qnently 

 deflexed point; lateral nerves numerous, regular and nearlj 

 lei, simple, lower ones straighl with a slightly curved sural 

 upper ones becoming progressively more arched upwards, when 

 near the apex of the leaf curved in so as nearly to join the 

 ity of the midrib; tertiary nervation so fim 

 ceptible in the fossil state. 



The specimens of these leave- contained in tl 

 Dr. Hayden, are quite numerous and pretty well ; 

 Although there is no fruit of Cornui as 1 with tb< 



there can belittle doubt that they are properlj hat 



