160 PALAEONTOLOGY OF CALIFORNIA. 



T. (? Sanguinolaria) Whitneyi, n. s. 



PI. 30, Fig. 242. 



Shell large, thin, compressed, subelliptical ; beaks a little in 

 advance of the centre, small; cardinal margins subequal, the 

 posterior side sloping downwards more obliquely than the ante- 

 rior; basal margin convex, most prominent a little behind the 

 beaks, sloping upwards in advance towards the anterior end. 

 Surface marked by fine, concentric lines. 



Figure, natural size. 



Locality: Jacksonville, Oregon, associated with many species of the lower divi- 

 sion of the California Cretaceous. Collection of Professor Whitney. 



I have not seen the hinge of this shell, and cannot therefore be positive in the 

 generic determination. In its compressed, inequilateral form, it resembles some 

 of the modern Sanguinolarias, and may possibly belong to that group. 



T. PARILIS, 11. S. 

 PI. 30, Fig. 243. 



Shell small, robust, nearly equilateral; beaks central, or nearly 

 so, elevated, with the margins sloping rapidly, nearly straight, 

 towards either end ; basal margin broadly and regularly convex ; 

 anterior end narrow and regularly rounded; posterior a little 

 broader and faintly subtruncated obliquely upwards and inwards. 

 Surface polished and ornamented by a few faint lines of growth. 



Figure, a little larger than natural size. 



Locality: A few specimens collected by Mr. Mathewson, near Martifiez. 

 This species approaches most nearly to T. Ashburnerii; but it is thicker, shorter, 

 more regularly equilateral, and the beaks are much more prominent. 



T. Hornii, n. s. 



PI. 30, Fig. 244. 



Shell long, narrow, subequilateral ; beaks small, subcentral ; 

 cardinal margins sloping slightly towards the ends ; anterior ex- 

 tremity regular, slightly broader than the posterior, which is a 



