ARNOLD— THE PALEONTOLOGY AND STUATKiUAniY OF SAN TEDltO. 141 



74. Cardium (Laevicardium) elatum Sowcrby. 



l>I.ATIi XX. 



Cardium e/atiini Sbv., Conch 111., Vol. I, 183S. Reeve, Conch. Icon., PI. VIII, 115^.41. Valen- 

 ciennes, Voy. Venus, PI. XVII, fig. i, 1846. 



Liocardium elatum Sby., Carpenter, Brit. Assn. Rept., 1863, p. 642. Cooper, 7lh Ann. Rept. Cal. 

 St. Min., 1888, p. 246. Keep, West Coast Shells, ]>. iSi, 1892. Williamson, Pioc. 

 U. S. Nat. Mus., Vol. XV, 1892, p. 190. 



LtBvicardium elatum Sby., Gabb, Pal. Cal., Vol. II, p. 99, 1869. Dall, Trans. Wagner In.st. 

 Sci., Vol. Ill, Part 5, 1900, p. 11 11. 



Shell large, oval, oblique, elongated, equivalve, somewhat inequilateral ; surface sculptured 

 by numerous faint, squarish, radiating ribs, and tine, wavy incremental lines; inner surface of margin 

 corrugated ; hinge strong, with one prominent cardinal and one prominent anterior lateral tooth in 

 each valve ; muscle-impressions distinct. 



Dimensions. — Long. 144 mm.; alt. 167 mm.; diam. 136 mm. 



This i.s the largest of the Cnrdiid'e, and is easily recognizable by its immense 

 size and nearly smooth surface. A line pair of this species, described above, and 

 figured, was found in the upper San Pedro series at the north end of the San Pedro 

 bluff. Another specimen was obtained by Dr. A. A. Wright and Mrs. Oldroyd in 

 the upper San Pedro deposits of Los Cerritos. This species is one of the typical 

 southern forms found in the upper San Pedro series. 



Living. — San Pedro to Mazatlan (Cooper). 



Pleiatocene. — San Pedro (Cooper; Arnold): San Diego (Gabb; Dall;. 



75. Cardium (Laevicardium) substriatum Conrad. 



Cardium substriatum Con., Jour. Phil. Acad. Sci , Vol. VII, 1837, p. 228, PI. XVII, fig. 2. 

 Liocardiutn substriatum Con , ^ cruentatum GoULD, {fide Carpenter, Brit. Assn. Rept., 1863, 



p. 642.) Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 246. Keep, West Coast 



Shells, p. 181, fig. 154, 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, 



p. 190. 

 Lcevicardium substriatutn CoN., Gabb, Pal. Cal., Vol. II, p. 99, 1869. Dall, Trans. Wagner Inst. 



Sci., Vol. Ill, Part 5, 1900, page in I. 



Shell small, obliquely ovate, ventricose, thin ; surface smooth, excejit for minute incre- 

 mental lines and nearly obsolete radiating stride ; one small sharp cardinal tooth in each valve ; two 

 narrow elongated lateral teeth in each valve, the posterior one in the left valve not prominent ; 

 interior of margin finely crenulated. 



Dimensions. — Long. 17 mm.; alt. iS mm.; diam. 13 mm. 



Distingui-shable by its small size and smooth surface. Specimens identified 

 by Dr. Dall. 



Rare in the lower San Pedro series of Doadman Island and San Pedro, and 

 in the upper San Pedro series of Deadman Island, San Pedro, Crawfish George's, 

 and Los Cerritos. Found also in the Pleistocene at Twenty-sixth Street, San Diego. 



Living. — Monterey to South America (Cooper). 



P/eisiocene.— Santa Barbara; San Pedro; San Diego (Cooper): San Pedro 

 (Arnold): San Diego (Arnold). 



