APPENDIX. 
323 
ligament margin a slightly curved line, about equal in obliquity to tbe anterior margin ; basal 
margin profoundly and nearly equally or regularly rounded. 
Locality. —Missiob: 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 Tres Pinos, in sandstone. 
20. m. decisa, Con., Pi. Ill, 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 tbe beak as tbe base ; basal margin tumid medially ; posterior ex¬ 
tremity subtruncated. 
Locality. —Tulare valley. 
[Note.— This specimen is a clay cast, and was found in a boulder that bad been washed down 
from tbe bills at the bead of the Tulare valley, about twenty miles west of tbe Canada de las 
Uvas. W. P. B.] 
TELLINA, Lin. 
22. t. diego an A, Con., Pl. III, fig. 28.—Ovate-eliptical, compressed, inequilateral, concen¬ 
trically striated. Slope carinated; posterior extremity suddenly produced or rostrated, and 
below tbe posterior basal margin. 
Locality. —San Diego, in sandstone. 
23. t. congesta, 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 tbe line of the base; posterior margin and posterior basal 
margin regularly rounded. 
Localities. —Monterey; Mission of San Diego ; Carmello. 
This interesting species is very abundant at Monterey, in indurated drab-colored clay. There 
is merely a chalky trace of tbe shell remaining. It occurs in a somewhat similar rock at Car¬ 
mello, and in sandstone at San Diego. Figure 14 is from San Diego ; 21 and 21a from Mon¬ 
terey ; and 18 from Carmello. 
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. mxcrodqnta, Con., PL III, fig. 29.— Rhomboidal, ventricose, thick in substance; an¬ 
terior side very short; umbonal slope rounded. Ribs 25, prominent, narrow, wider posteriorly, 
