1922] Fauna from the Eocene of Washington 31 



Collection) on Coal Creek, Cowlitz County, about one-half of a mile above old 

 dam, Section 11, Township 8 North, Range 3 West. 



GENUS CREPIDULA LAMARCK 



CREPIDULA DICKERSONI n. sp. 



Plate XI, Figure 2 ; Plate XII, Figure 9 



Crepidula n. sp. Dickerson, 1915, Proc. Cal. Acad. of Sci., Fourth Series, vol. 

 V, No. 3 pi. 5, fig. 6 a, b. 



Description. Shell small to medium in size ; sub-ovate ; whorls about three 

 and smooth except for lines of growth; spire twisted, apex raised above the 

 margin of the body whorl ; shell varies in height ; septum well developed, ex- 

 tending about half the length of the shell, outer half of the margin of the 

 septum convex, inner half concave. 



This shell is very abundant in a lower, coarse, sandy layer at locality 329. 

 The most common size of the species is about 6 mm. in length, the largest speci- 

 men is 12 mm. in length. 



Species named in honor of Dr. Roy E. Dickerson of the California Acad- 

 emy of Sciences, by whom it was first figured, and who has described a large 

 number of forms from this locality. 



Dimensions. Altitude (length) 12 mm.; width of body whorl 10 mm.; 

 height above base 6 mm. (These measurements were taken on the largest speci- 

 men. ) 



Occurrence. At locality 329 (University of Washington Palaeontological 

 Collection) west bank of the Cowlitz River near Vader, Lewis County, Section 

 28, Township 11 North, Range 2 West. 



CREPIDULA STILLWATERENSIS n. sp. 

 Plate XI, Figure 24 



Description. Shell large and globose; whorls two, smooth; anterior end 

 rising abruptly and only slightly convex on top ; spire not twisted ; apex situated 

 just above the margin of the shell ; body whorl elevated. 



Dimensions. Altitude 15 mm. ; width of body whorl 12 mm. ; height 10 mm. 



