— 55 — 



the lignitic laminae, make it impossible to separate this from some other 

 species, but more specimens may distinguish it better. 



Anodonta (nuttalliana) lignitica n. var. (PL V, Fig. 58.) 



Form oblong-ovate, the ends rather obtusely pointed near their mid- 

 dle, dorsal line straight along the hinge-margin for about one third the 

 total length; anterior end truncately sloping to an obtuse angle of about 

 forty-five degrees near the middle, then curving gradually to the rounded 

 basal margin; posterior end curving upward more abruptly and forming 

 a more obtuse angle above the middle, then concavely incurved upward 

 to meet the straight hinge-margin. Beaks one third the distance from 

 anterior end, umbonal ridge slight, with a narrow compressed area above 

 it, extending backward to posterior angle. Length, 3 inches; height at 

 umbos, 1.50; breadth unknown, but was apparently very slight. 



I have made this description as full as possible to show the differences 

 between this and the living Anodontas of this State, which I think are 

 well marked, though they are so variable. Some of the fossil forms 

 from the Quaternary of Nevada come nearer to this, however. It is, of 

 course, still uncertain whether it is an Anodonta, the hinge not having 

 been examined, but most probably it is a Pliocene Tertiary fossil. 



Amnicola yatesiana n. sp. (PI. V, Fig. 60.) 



Small, sub-globular, slightly tabulated at the upper part of the 

 whorls, spire acute, conical, whorls four and a half, the body-whorl 

 forming two thirds of whole length, obtusely rounded at base. Mouth 

 suboval, a deep umbilical pit behind columellar lip. Length, 0.11 inch; 

 breadth, 0.08; spire, 0.04; mouth, 0.06 long, 0.04 wide. (Figure five 

 time3 natural size.) 



This little shell is found in great numbers in Pliocene deposits on 

 both sides of San Francisco Bay — at Mission San Jose on the east, also 

 near Stephen's Creek, and near Los Gatos on the west. Carinifez new- 

 berryi and other living species occur with it in localities, also some 

 species that may, like this, be extinct. It differs from the A. longinqua 

 Gould (found lately living at Lake Pt., Utah), in the tabulated whorls. 

 Mr. Watts obtained specimens taken from an artesian well at Lambert- 

 son's, Tulare Co., 1,058 feet deep, with Sphaerium dentatum Hald., a 

 species still living east of the Sierra Nevada. 



