174 Kcmsas Academy of Science. 



DESCRIPTION OF FOSSILS OBTAINED BY THE 



WRITER. 



MOI.LUSCA. 



Class Pelecypoda ; Order Prionodesmacea. 

 Family I Solemyacid^ ; Genus Solemya Lam. ♦ 



Shell Soleniform, equivalve, low-beaked, edentulous, gaping. 



1. Solemya ventricosa Conrad, Plate I, fig. 1. 



Solemya ventricosa Con. Wilkes's ^Expl. Exped., vol. X, p. 723, pi. 17, 

 figs. 7-8. 



Conrad's description:^^ " Oblong, ventricose ; dorsal and ventral 

 margins straight and parallel; anterior side narrowed, the margin 

 orbiculate ; posterior margin scalloped ; the interior half truncated 

 obliquely inward ; beaks distant from the anterior extremity; lat- 

 eral surf ace- smooth, radiated with narrow bands." 



This is a very common species in both the upper and lower 

 series of the Oligocene-Miocene rocks at Gettysburg, Wash., but is 

 most abundant in the upper series. 



Miocene at Astoria Ore. ( Conrad ) ; .Oligocene-Miocene, Gettys- 

 burg, Wash. ( Reagan) . 



Superfamily Nuculacea; Family VI Nululid^; Genus iVwcttZa Lamarck, 

 "Shell trigonal, with the umbones turned towards the short pos- 

 terior side; smooth or sculptured; epidermis olive; interior pearly; 

 margins crenulated; hinge with prominent internal cartilage-pit, 

 and a series of sharp teeth on each side; pallial line simple. Type, 

 Area nucleus Jjam." (Arnold.) 



Subgenus Acila H. & A, Adams, 

 Shell with divaricate structure. 



2. Nucula (Acila) castrensis Hinds, Plate I, flig. 2. 



Nucula castrensis Hinds, Proc. Zool. Soc, 1843, p, 98; also, Hinds Voy. Sul- 

 phur, p. 61, pi. 17, fig. 5. 

 Niicula (Acila) castrensis H, & A, Adams, Genera. Rec. Moll., vol. 2, p. 



545. 

 Nucula divaricata Con., Wilkes's Expl. Exped., vol. X, p. 725, pi. 18, fig, 



6; also, Am. Jour, Sci. 1848, p. 432, fig. 1. 

 Nucula decisa Con., P. R. R. Rept., vol. V, p, 222, pi, 3, fig, 19, 

 Nucula conradi Meek, Smithsonian Check List (fide Gabb, Pal. Cal., vol. 



11, 1869, p. 102). 

 Acila castrensis Hinds, Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 227; 



Williamson, Proc, U. S. Nat. Mus., vol. XV, 1892, p. 192. Dall, Trans. 



Wagner Inst. Sci., vol. Ill, 1898, p. 572. 

 Acila lyalli Baird (fide Carpenter, Brit. Assn. Rept,, 1863, p, 644). 

 Nucla (Acila) castrensis Hinds, Arnold, Mem. Cal. Acad, Sci,, vol. Ill, pp. 



95. 96. 



33. Loc. Cit. 



