FAUNA OF THE BICK>NELL SANDSTONE. 4<>7 



Taylorville, California. Europe. 



Gryphsea bononiformis, n. sp, Ostrsea bononise, Sauv;, as figured by 



de Loriol et Pellat ; Portlandian. 



Entolium costaium, n. sp. 



Oxytoma, n. sp. 



Trigonia obliqua, n. sp. Trigonia michelloti, de Lorio] : Port- 



landian. 



Trigonia plamasensis, n. sp. Tri</<nii<i lusitanica, as figured by 



Choffat ; Portlandian. 



Trigonia naviformis, n. sp. Trigonia navis; inferior Oolite. 



c/iniiiiitziii, n. sp. Chemnitzia atfAteto, d'Orb. ; Corallian. 



Rhacophyllites, n. sp. 



The group of Trigonia glabrae, to which 7 7 . obliqua belongs reached its 

 acme in the Portlandian, the species being both rare and comparatively 

 small in the Lias and inferior Oolite. T. obliqua is of extraordinary size 

 and shows the incomplete costse of the Portlandian species. The group 

 of Trigonia to which T. plumasensis belongs is very peculiar in the char- 

 acteristics of the costa* and the ornamentation of the anal area, and it 

 has hitherto been represented in Europe only by the unique form. T. lusi- 

 tanica, found only in the highest Jura of Portugal. Besides these two 

 large species there is also in T. naviformis an equally large representative 

 of another peculiar and hitherto unique style of ornamentation. This. 

 as its name implies, is similar to T. navis* of the inferior Oolite in Ger- 

 many, a species hitherto considered to be the only representative of a 

 very distinct group, the Trigonia scaphoidse, and having a pattern of nota- 

 tion not (bund in any other species (except T. naviformis) and a narrow 

 chorologic range. 



The group of the Trigonia undulata is represented by a species also of 

 extraordinary size, but the Trigonia clavellatse, the group more largely 

 represented than any other in the inferior Oolite (if one can judge from 

 thesingle specimen obtained in (he Bicknell sandstone) is not materially 



modi lied. 



Bicknell Tuff. — Above the sandstone and in immediate contact with it 

 is a tuff described by Mr. Diller, which contains in part the same specie- 

 as the sandstone, and the fossils indicate the same fauna. Nevertheless 

 it should he noticed that it contained no remains of Ti'igonia, and that 

 the fauna has not been critically examined. 



Ilincliinan Tuff (Stylina Bed). — The presence of the same species of 

 Rhacophyllites as thai found in the Bicknell sandstone indicates the con- 

 tinuity of the fauna of this bed with that of the preceding; hut. on the 



i lie differences between Hie <»<• are quite sufficient t" separate them as distinct -i i.--. bul 



they have the same styie ol i in • specially "ii the anterioi region. 



