CRETACEOUS FOSSILS. 120 



lip to the base of the superior process; upper whorls marked by 

 fine longitudinal ribs, crossed by a few fine, impressed lines, 

 most distinct above. 



Figure a, natural size; Fig. b, magnified view of a young specimen, showing 

 the sculpture. 



Localities: Orestimba Canon; Martinez; Puerto CaHon, Stanislaus County; 

 Siskiyou Mountains. 



A. EXILIS, n. S. 

 PI. 29, Fig. 231. 



Shell minute; spire high; whorls six, upper whorl convex, 

 the apex blunt; body whorl biangular, the upper angle very pro- 

 minent; canal produced, straight; lip unknown. Upper whorls 

 ornamented by curved ribs placed somewhat obliquely; on the 

 body whorl these ribs incline forward to the upper angle of the 

 whorl, and then downwards and backwards, becoming obsolete 

 anteriorly ; below the lower angle, they are crossed by smaller 

 revolving lines, producing a somewhat cancellated appearance. 



Figure, two and a half times natural size. 



Locality: A single, imperfect specimen, collected by Mr. Mathewson at Mar- 

 tinez. 



CYPR^EA, Linn. 



? C. Bayerquei, n. s. 



Shell ovoid, convex, widest to- 

 wards the upper end, gradually taper- 

 ing below; under surface flattened. 

 Spire hidden. Mouth narrow, linear; 

 outer lip rather broad. Surface un- 

 known. A cast. 



Locality: Clayton, Contra Costa County. Col- 

 lection of Mr. Bayerque. 



This species, of which I have only seen a 

 pal. vol. I. — 17 



