FOSSILS FROM BIG Bx\R, CALIFORNIA 381 



Nilsonia orieiitalis minor Font. 



Sagenopterispaucifolia WavA. 



Sagenopteris grandifoUa Font. 



Hausmannia cf. H. forschammeri dentata Moller. 



Sphenolepidiuiii oregoncnse Font. 



Pagiophyllum falcatum ? 



Taxites zamioides Sew. 



Podosamites lanceolatus minor Heer. 



Seed, probably eycadaceous. 



Doctor Knowlton remarks that — 



"These fossils prove bej'ond question that the beds containing them are sim- 

 ilar ill age to the Jurassic of Oregon, since all but three of the forms (Oinjchi- 

 opsis (fruit), Hausmannia, and Pagropliyllmn falcatum) are common to the 

 two areas." 



FOSSIL SHELLS 



Shells have been found in the same beds with the plants at both the 

 Pattison and Wilshire mines, so there is no doubt whatever as to their 

 association. The collections made at various times were referred to Doc- 

 tor Stanton, who reports the following forms : 



Pecten sp. 



Mytilus sp. 



Aticella crassicolUs Keyserling. 



Gyprina sp. ? 



IJnio sp. — undescribed species represented by several good casts. 



Doctor Stanton states : 



"The fossils from Big Bar, California, area are certainly upper Knoxville 

 and hence Lower Cretaceous, as shown by the presence of typical specimens of 

 Aucella crassicolUs. The other invertebrate fossils from the same area are 

 closely associated stratigraphically with the Aucella, but as they are either un- 

 described or unidentifiable species, they do not throw any additional light on 

 the question of the age of the beds. Two of the lots consist entirely of an in- 

 teresting new species of Uuio, which is important as showing that part of the 

 beds at Big Bar were deposited in fresh water." 



As to the relation between the Aucella and Unio : The Aucella crassi- 

 colUs, as far as yet observed, is limited to a bed of coarse sandstone 4 feet 

 in thickness and has been found only on the western side of the area, on 

 the upper bench of Pattison mine, interstratified with the plant beds, 

 about 6 feet above their base. The Unio occurs most abundantly in a 

 thin layer of clayey shale immediately below the Aucella bed. It occurs 

 also in shales 50 feet above the Aucella bed and indicates the alternation 



