es 
‘APPENDIX, 323 
ligament margin a slightly curved line, about equal in obliquity to the anterior margin ; basal 
margin profoundly and nearly equally or regularly rounded. 
Locality.—Mission of San Diego. 
MERETRIX, Lam. 
19. M. UNIOMERIS, Con., Pl. III, fig. 20.—Ovate, very inequilateral, convex; posterior side 
cuneiform ; ligament margin very oblique, rectilinear; posterior extremity truncated, direct ; 
beak distant from anterior margin. 
Locality.—Monterey county, 18 miles south of Trés Piños, in sandstone. 
. 20. M. DECISA, Con., Pl. III, fig. 27.—Subquadrate, convex, very inequilateral; ligament 
slope very oblique, nearly straight; posterior extremity truncated ; cardinal and lateral teeth 
robust, [Cast.] | 
Locality.—Ocoya creek, in friable ferruginous coarse sandstone. [For the associate fossils, 
see plates vii, viii, and ix. 
21. M. TULARANA, Con., Pl. III, fig. 22 and 22a.—Suboval or subtriangular, inequilateral 
convex anteriorly ; compressed and cuneiform posteriorly, anterior extremity acutely rounded 
and as nearly in a line with the beak as the base; basal margin tumid medially ; posterior ex- 
tremity subtruncated. 
Locality.—Tulare valley. 
[Nore.—This specimen is a clay cast, and was found in a boulder that had been washed down 
from the hills at the head of the Tulare valley, about twenty miles west of the Cañada de las 
Uvas. ' WB. Bi 
TELLINA, Lin. 
22. T. DIEGOANA, Con., Pl. IH, fig. 28.—Ovate-eliptical, compressed, inequilateral, concen- 
trically striated. Slope carinated; posterior extremity suddenly produced or rostrated, and 
below the posterior basal margin. 
Locality.—San Diégo, in sandstone. 1 
23. T. coxazsTA, Con., Pl. III., fig. 14, 18, 21, and 21a.—Subtriangular, ventricose, inequi- 
lateral; anterior margin obliquely truncated ; anterior basal margin sub-rectilinear, oblique, 
extremity angulated, much above the line of the base; posterior margin and posterior basal | 
margin regularly rounded. 
Localities.—Monterey ; Mission of San Diégo ; Carmello. 
This interesting species is very abundant at Monterey, in indurated drab-colored clay. There 
is merely a chalky trace of the shell remaining. It occurs in a somewhat similar rock at Car- 
mello, and in sandstone at San Diógo. Figure 14 is from San Diego; 21 and 21a from Mon- 
terey ; and 18 from Carmello. : P 
24. T. PEDROANA, Con., Pl. III, fig. 17.—Subtriangular, inequilateral, compressed ; anterior 
dorsal margin oblique, rectilinear ; anterior extremity truncated, posterior margin regularly 
rounded, basal margin subrectilinear. 
Locality —San Pedro. Recent formation. 
A thin smooth species, of which only one valve was obtained. 
ARCA, Lin. 
25. A. MICRODONTA, Con., Pl. III, fig. 29.—Rhomboidal, ventricose, thick in substance; an- 
terior side very short; umbonal slope rounded. Ribs 25, prominent, narrow, wider posteriorly, 
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