138 PALAEONTOLOGY OF CALIFORNIA. 



spire not visible. Surface marked only by irregular, concentric 

 lines and undulations. Aperture semi-elliptical; outer lip thick- 

 ened internally, and finely crenulate ; inner lip thickly incrusted, 

 curving downwards towards the mouth, straight and crenulated 

 on the ed";e. 



Figures, natural size. 



Locality: Three specimens were collected by Dr. J. A. Vcatch at Tuscan Springs, 

 Tehama County. The lino from the apex to the outer lip varies in all the speci- 

 mens ; in one it is straight, in another quite convex. 



LYSIS, N. Gen. 



General form like Stomatla. Shell subspiral, very oblique; 

 spire moderately prominent; whorls costate. Aperture narrow, 

 oblique ; outer lip simple ; columcllar lip straight, and rather 

 heavily incrusted. Umbilicus broad, but entirely closed by a 

 concave expansion of the incrusting layer of the inner lip. 



L. duplicosta, n. s. 



PI. 21, Fig. 98. 



Shell oblique; spire not very prominent; whorls three, rapidly 

 increasing in size ; suture impressed. Surface marked by from 

 five to seven prominent ribs, each grooved along its whole length 

 by a sharp, deep channel ; the interspaces are broad, regularly 

 and rather deeply concave, and marked by a few fine revolving 

 lines. Mouth very oblique, rounded posteriorly, and subacute in 

 advance; outer lip simple; inner lip straight when viewed from 

 the front ; seen laterally, it is very slightly concave. Umbilical 

 region broad, concave, especially above and towards the outer 

 margin; covered by an expansion of the incrusting substance on 

 the inner lip ; umbilical margin sharply carinated. 



Figures a and b, natural size. Fig. c, a magnified section across the ribs, to show 

 the groove. 

 Locality: Texas Flat, Placer County (Division A.). 



