NEW SPECIES FROM THE SANTA LUCIA MOUNTAINS 455 
Dimensions: Length, 18 mm.; height, 1o mm.; thickness of closed valves, 
5mm. 
Cf. Yoldia arata Whiteaves, Geol. Surv. Canada, Mesozoic Fossils, 1, Pt. II, 
p. 233, Pl. XXXI, Fics. 4 and 4a. 
A single specimen, rather poor, but showing clearly the attenuate posterior 
end, elongation, strong concent-ic striations, and shallow concave slope of 
hinge from beaks to posterior end. 
Dimensions: Length, 
14mm.; height, 63 mm.; 
thickness of closed valves, 
about 4 mm. 
Nucula (acila) sp. 
Shell small, nearly 
equilateral; subovate, 
Fic. 1.—Alaria fairbanksi, Fic. 2.—Inoceramus lucianus, one-half natural 
natural size. size. 
moderately convex but depressed toward basal margin. Ribs divaricate from 
imaginary line running from beak to basal margin slightly anteriorly. Extreme 
length of shell from 7 to 15 mm. The wide range and common characteristics 
of the Nucula (acila) give it little determinative value. 
Inoceramus lucianus (n. sp.), FIc. 2. 
Several imperfect and broken specimens are in the L.S.J.U. collection. 
The one giving the best conception of the type is a cast of a left valve. The 
form is ovate or Subquadrate, cardinal margin straight, basal margin semi- 
circular. The beaks are rather low but pointed. The ribs on the type speci- 
men are flattened by the pressure to which the rock has been subjected, but 
