12 PALEONTOLOGY OF CALIFORNIA. 



C. (E.) VETUSTA, n. 8. 

 PI. 2, Fig. 19. 



Shell small, spire not so long as the mouth; whorls five or 

 five and a half, increasing rapidly in size, angnlated and trun- 

 cated ahove, sloping convexly inwards below ; suture moderately 

 well marked, undulated. Surface marked by longitudinal ribs 

 commencing at the suture, passing obliquely backwards to the 

 angle, and then downwards to the anterior end; these are 

 crossed by fine revolving square ribs, with broad, flat interspaces, 

 and with sometimes smaller ones intercalated. Aperture long, 

 biangnlar above, and narrowing in advance; inner lip heavily 

 incrusted, bearing two heavy folds, and two or three fine ones 

 above. Umbilicus narrow, covered by a very thick expansion of 

 the inner lip, and in one specimen showing a slight perforation. 



Figure, magnified. Length about one inch. 



Locality : Found thus far only in the Miocene, south of Martinez. Two or 

 three specimens collected by Mr. Mathewson. 



It is possible that a further study of the species would prove that the perforated 

 umbilicus mentioned above is not a constant character. It seems to be, in this 

 instance, rather the result of accident than a specific character. 



BITTIUM, Leach. 



B. ASPERUM. 



PI. 2, Fig. 20. 

 (Tuibonilla aspera, Gabb; Proc. Philada. Acad. Nat. Sci., 1861, p. 308.) 



Shell long, slender; whorls twelve or thirteen; nuclear whorls 

 smooth, others marked by ten or twelve strong, longitudinal ribs, 

 crossed by four or five sharp, filiform, revolving ribs with broad 

 interspaces; suture deep. Under surface smooth, or marked by 

 one or two ribs near the angle. Mouth longer than broad, pro- 

 duced below and slightly expanded at the columellar angle; lips 

 acute. 



