572 



ARNOLD AND HANNIBAL— MARINE TERTIARY [April 19, 



by basic volcanic flows and agglomerates, until on the Santiam 

 River east of Albany and the Nehalem River in Clatsop and Colum- 

 bia Counties only igneous rocks are present, the few fragmentary 

 fossils on which the determination of the age of these lavas is based 

 being obtained from coarse tuffs. 



Partial List of Species in the Arago Horizon of the Tejon Series {Middle 

 Eocene) of Southwestern Oregon and the North Coast of Washington. 



99 ^'^ 



Pelecypoda: 



Cardium breweri Gabb 



Cardium coo peri Gabb 



Corbida horni Gabb 



Crassitelliles compacla Gabb 



Crassilelliles uvasana Conr 



Cyrena brevidens White 



Glycymeris cor Gabb^i 



Macrocallista conradiana Gabb 



Marcia quadrata Gabb 



Meretrix horni Gabb 



Millha lurneri Stanton 



Modiolus ornatus Gabb 



O^trea idrixnsis Gabb 



Septif r dichrotomus Gabb 



S ten pirallelus Gabb 



Tellina horni Gabb 



Tellina longa Gabb 



Tellina remondi Gabb 



Venericardia horni Gabb (var. with obsolete ribs)' 



Gasteropoda: 



Amauropsis alveala Conr 



Calyptraea excentrica Gabb 



Conus siniiatus Gabb 



Ficopsis horni Gabb 



Loxotrema turrita Gabb 



Olivella mathewsoni Gabb 



Polinices globosa Gabb^^ 



Polinices horni Gabb 



Polinices shumardiana Gabb^' 



Potamides carbonicola Cooper^^ 



Siniitn obliqiium Gabb 



Strepsidura whitneyi Gabb 



Triionimn californicutn Gabb 



Turris io Gabb 



Turritella uvasana Conr 



Scaphopoda: 



Denlalium stramineiim Gabb . . . , 

 Brachiopoda : 



Terebratulina iejonensis Stanton. 



X 



19 Species supposed to be characteristic of this horizon. 



