172 PALAEONTOLOGY OF CALIFORNIA. 



MARGARITELLA, M. & H. 



M. ANGULATA, II. S. 

 PI. 28, Fig. 55. 



Shell small, thin, highly polished, spire elevated; whorls four 

 and a half, convexly flattened on the sides, more or less truncated 

 above ; body whorl very slightly convex on the base. Surface 

 bearing one, two, or three strongly impressed lines near the suture, 

 crossed by oblique impressed lines forming variable series of cren il- 

 lations; these oblique lines rarely extend far down on the sides, 

 but hold the same direction as the lines of growth, which can 

 occasionally be traced their entire length; besides these, there 

 are sometimes faint revolving lines visible over the entire surface, 

 more constant on the base ; umbilicus moderate, its margin evenly 

 crenulated, its internal surface marked by strong revolving and 

 radiating lines. Aperture subquadrate, margins simple. 



Length, .25 inch; width, .23 inch. 



From the Martinez or Chico Group, Martinez. There is a small deposit of the 

 latter group near Martinez, and judging from the lithological character of the 

 specimens, they seem to have come from it ; they were sent me by Mr. Mathewson. 



This species can be distinguished from M. crenulata by its higher spire and 

 narrower umbilicus ; they approach each other in the crenulation of the top of 

 the whorl and the umbilical margin. 



ACM^EA, Esch. 

 ? A. Tejonensis, n. s. 



PI. 28, Fig. 56. 



Shell small, low, ends unequal ; anterior end broad, sides con- 

 verging posteriorly; posterior end narrow, rounded; apex sub- 

 central, slightly curved forwards. Surface marked by a few con- 

 centric lines, and six or eight faint radiating undulations. 



Length, .35 inch ; greatest width, .25 inch; height, .1 inch. 



