xo. 1617. NEW CRETACEOUS AND TERTIARY FOSSILS—ARNOLD. 36 7 
Rock; locality No. 117, on east branch of North Fork of Waddell 
Creek, Big Basin (R. Arnold). Also at U.S. Geological Survey local- 
ity Nos. 4063 and 4064, Porter, Chehalis County, and locality No. 
4071, Restoration Point, Kitsap County, opposite Seattle, Washing- 
ton (R. Arnold). 
Genus TELLINA Linnezeus. 
TELLINA LORENZOENSIS, new species. 
Plate XXXIII, fig. 1. 
Description.Shell attaining a length of 40 mm., width a little 
over five-eighths of length, oblong, compressed, slightly mequivalve, 
anterior end evenly rounded, posterior end biangular and narrower 
than anterior; umbo small, central, though sometimes, as in type, 
placed a little in front of middle; sides making an angle of 125° at 
the umbo; anterior dorsal margin very gently curved near umbo, 
becoming rapidly more curved near extremities; ventral dorsal mar- 
gin very gently curved for whole length to upper posterior angle; 
a moderately sharp fold, on which the lines of growth are particu- 
larly prominent, extends from the umbo to the lower posterior angle; 
a faint indication of a reentrant angle often occurs in the margin at 
the end of the fold; base nearly straight, curving quite rapidly at 
ends. Surface sculptured by numerous slightly unequal concentric 
lines. Left valve similar to right except that instead of being very 
shehtly flexed upward at the posterior extremity, it is flexed down- 
ward. 3 
IONS: —Length, 40 mm.; latitude, 26 mm.; diameter single 
valve, 3 mm. 
NV oven Une species is very closely allied to 7. rubescens Hanley 
from the recent fauna of the west Mexican coast, but may be dis- 
tinguished by its more anterior umbo, shghtly sharper posterior 
fold, less sharply angular and usually less flexed posterior extremity, 
and considerably finer concentric sculpture. 7’. lorenzoensis also re- 
sembles 7’. eburnea Hanley of the Panama fauna, but is smaller and 
has finer sculpture and other minor differences. It is unlike any 
of the other west coast Oligocene and Miocene forms in having a 
more central umbo. Named for the San Lorenzo formation, of 
which it is believed to be characteristic. 
Type.—Mold of right valve, from which specimen figured is the 
cast; Cat. No. 1654389, U.S.N.M. (Locality No. 115.) 
Horizon.—San Lorenzo formation, Oligocene. 
Localities—Santa Cruz quadrangle, Santa Cruz County, locality 
No. 107, on small ravine off Boulder Creek, 24 miles north of 
Eagle ioe (R. Arnold; I. Anderson) ; locality No. 115, on south- 
east branch of South Pork of Waddell es Big Basin (R. Arnold, 
W. R. Hamilton). 
