380 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
lower spire and in having a carinated body whorl, but no angles on 
body whorl; it differs from the last in being much broader and in 
having less prominently sculptured upper whorls, although it re- 
sembles the last in the prominence, width, and general character of 
its carina. Poorly preserved specimens from locality 12, which have 
been assigned to A. santacruzana, show faint indications of two or 
three rather prominent raised lines on the body whorl, somewhat 
similar to but very much less prominent than the nodose revolving 
ridges on the middle of the body whorl in A. barkerianum Cooper. 
With the exception of A. stnuata Gabb and A. stanfordensis, new 
species, which occur in the upper Miocene, all of the members of this 
genus on the west coast are believed to be confined to the lower 
Miocene or “Agasoma zone ” of Merriam.* 
Named for the Santa Cruz quadrangle. 
Type.—slightly imperfect young specimen, L. S. J. U., No. 1072. 
(Locality No. 1.) 
FHorizon.—V aqueros eansenaiiom, lower Miocene. 
Localities—Santa Cruz quadrangle, San Mateo County, locality 
No. 1, on hill north of road, one-half mile north-northeast of the north 
end of Searsville Lake; howelhy No. 12, Mindego Creek, 1 mile above 
its confluence with ipa Creek (R. ivanell) = also found at U.S. 
Geological Survey locality No. 4631, 10 miles north of Coalinga, 
Fresno County. (R. Arnold, Jas. H. Pierce.) 
MONTEREY (MIDDLE MIOCENE) SPECIES. 
[Jala VIO IDA. 
Genus VENERICARDIA Lamarck. 
VENERICARDIA MONTEREYANA, new species. 
Plate XXX/V, fig. 4. 
Description.—Adult shell attaining a length of at least 10 mm., 
width about three-fourths of length, suboval in outline, compressed ; 
umbones near anterior extremity, small, turned toward the front; 
anterior extremity short, regularly rounded; posterior extremity long, 
obliquely projected below, quite sharply rounded; surface sculptured 
by about 22 moderately broad radiating ribs and numerous subequally 
spaced concentric lines, radiating and concentric systems together 
giving a cancellate appearance. 
Dimensions.—Length, 10 mm.; altitude, 7 mm.; diameter, 1 valve, 
1+ mm. 
Notes.—This species is probably allied to V. barbarensis Stearns 
and V. ventricosa Gould. It has more anterior umbones and has more 
numerous ribs (22 instead of 18) than the former, and is mnt flatter 
«Bull. ‘Tres. Geol., Univ. of Gaiinanin, III, 1904, p. 377 et seq. 
