126 University of California Publications in Geology [Vol. 8 



radial line which sets off the flat dorsal portion of P. barrowsi is not 

 central nor is it deeply eroded. 



This Pinna is also found in the lower Tejon, southwest of Mount 

 Diablo, near Pine Creek, at University of California Locality 1489. 



Named in honor of Mr. A. L. Barrows. 



LIMA (9) CLAYTONENSIS, n. sp. 

 Plate 7, figures 9a, 9b 



Shell inflated, with radial sculpture; rounded and almost .sym- 

 metrical. Ratio of length to height about .65 to 1. Beak prominent, 

 acute, and in some specimens compressed. Hinge line short and 

 straight with about twelve small striations perpendicular to hinge 

 line. These striations may be plications within the shell wall, revealed 

 by th breaking away of the inner shell layer. Area, narrowly elliptical 

 and central. Basal margin, rounded. Ribs — about thirteen in number 

 — are acute-angled and beaded ; the interspaces are the same in width 

 as the ribs. 



Dimensions. — Length, 2.5 mm. ; height, 3.8 mm. 



Occurrence. — Martinez Group, two miles due east of Clayton in 

 beds near base, University of California Locality 1592. It also occurs 

 at localities 1546 and 1557. (See table of localities.) 



The various features described were recognized from a study of 

 four different specimens. This little shell is quite characteristic of the 

 basal beds or beds about 100 feet above the base at its type localities. 

 It is one of the few species found in the Martinez shales. 



Named for its occurrence near Clayton. 



LIMA(?) HASELTINEI, n. sp. 

 Plate 8, figure 2; plate 9, figure 11 



Shell large, slightly oblique, nearly equivalve, moderately convex; 

 beak prominent, pointed, anterior, prosogyrate ; hinge, edentulous, 

 long, straight ; ears not markedly set off from rest of shell, the pos- 

 terior one being the larger ; anterior end broadly rounded ; posterior, 

 slightly truncated; ventral margin, arcuate; decoration consists of 

 numerous squarish radial ribs with very narrow interspaces. 



Dimensions. — Height of large specimen, 130 mm. ; length, 135 mm. ; 

 convexity, 27 mm. 



