PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 509 



cipal denticles receiving the terminations of the nerve branches ; the 

 sinuses between these sometimes pkiin, sometimes set with a few small 

 teeth ; nervation delicate, about 8 branches given off from each side of 

 the midrib. 



Formation and locality. — Miocene 1 Tertiary strata, Bridge Creek, 

 Oregon. Collected by Prof. Thomas Condon. 



31. Alnxis Alaskan a, n. sp. 



Leaf large, oblong-ovoid, acuminate, rounded, or slightly heart- 

 shaped at base; nervation crowded, 16 to IS branches on each side of 

 the midrib; margins set with very numerous, small, uniform, acute 

 teeth. 



Formatioji and loGalitj/. — Tertiary strata, Kootzanoo Archipelago, 

 latitude 57° 35', longitude 134° 19', Alaska Territory. Collected by U. S. 

 steamer Saginaw, February 18, 18()9. 



32. Alnus grandiflora, n. sp. 



Leaves 4 to 5 inches in length by 3 inches in width ; ovate ; rounded 

 or wedge-shaped at the base; blunt pointed at the summit; margins 

 coarsely dentate; nervation strong, crowded; 12 or more parallel 

 branches on either side of the midrib, the intervals between these 

 crossed by numerous parallel, mostly straight nervules, dividing the sur- 

 face into oblong, quadrangular areoles. 



Formation and localiti/. — Tertiary strata, Cook's Inlet, Alaska. Col- 

 lected by Captain Howard, U. S. N. 



33. Plat ANUS aspera, n. sp. 



Leaves attaining a diameter of 1 foot or more; petioled ; rounded at 

 the base more or less; three-lobed, sometimes nearly ovoid; nervation 

 strong, about 9 branches on each side of the midrib ; margins deeply, 

 and often compoundly, toothed. 



Formation and localiti/. — Miocene ? Tertiary, Bridge Creek, Oregon. 

 Collected by Prof. Thomas Condon. 



34. Fraxinus integrifolia, n. sp. 



Leaves short-petioled or sessile ; lanceolate ; broadest near the base, 

 which is abrni)tly narrowed and wedge-shaiJed ; summit narrowed, ex- 

 tremity rounded ; margins entire; nervation reticulate, camptodrome; 

 lateral branches connected in elegant festoons near the margins ; inter- 

 vals filled with net- work of roundish, polygonal meshes. 



Formation and locality. — Tertiary strata, Bridge Creek, Oregon. Col- 

 lected by Prof. Thomas Condon. 



35. Prunus variabilis, n. sp. 



Leaves short-petioled, very variable in form ; lanceolate or broadly 

 lance-ovate, 2 to 3 inches long by 1 to 2 inches wide ; acuminate at the 

 summit, wedge-shaped at base; margins thickly set with minute, acute, 

 appressed teeth. 



