102 Kansas Academy of Science. 



SuBGLACiAL TiLL. — Tliis is a gray, blue or black clay. It is very 

 hard, and when dry shows a joint structure. In many places it is 

 a gumbo. At places where it is the surface rock, it is very poor 

 soil. It is of great thickness, and underlies the entire region to 

 the foot-hills. It was deposited in sea- water, as its marine shells 

 attest. 



Fossils from the Subglagial Till.— The fossils figured and 

 described here were taken from the subglacial till one mile below 

 Fish Point, on the Bellingham Beach side of the Lummi Indian 

 reservation. 



Leda fossa ( Baird) . Figures la and 16. 



"Shell small, elongate, convex, thin ; umbones anterior, turning^ 

 slightly toward the posterior end, which is elongated, narrow, and 

 truncated ; anterior end short and evenly rounded ; sculpture nearly 

 obsolete, a few concentric lines discernible ; escutcheon long, narrow, 

 smooth, and deep-set; an elongate process on middle of interior of 

 posterior end; hinge with small internal cartilage pit, and numer- 

 ous sharp teeth on each side." 



Dimensions: Length, 15 mm.; alt., 8.5 mm.; diam., 5 mm.; 

 umbo to posterior end, 10 mm.; to anterior end, 7 mm. 



Distinguishable by lack of sculpture. 



Living: Puget sound (Carpenter). 



Pleistocene: San Pedro, Oal. (Arnold). 



Leda hamata (Carpenter) . Figures 2a and 2b. 



Shell similar to to Z. fossa, except its surface is sculptured by 

 strong concentric, raised lines ; a raised band, strongly transversely 

 sculptured by continuations of the concentric ridges, passes from 

 the umbo around the escutcheon to the posterior end; escutcheon 

 deep-set, smooth. 



Dimensions: Length, 11 mm.; alt., 6 mm.; diam., 4 mm.; umbo 

 to posterior end, 7.5 mm.; to anterior end, 5 mm. 



Living: Santa Barbara to Catalina, Cal. (Carpenter). 



Pleistocene: San Pedro and San Diego, Cal. (Arnold). 



Pliocene: Deadman island, San Pedro, Cal. (Arnold). 



Leda tenuisulcata (Stimp.) Figure 3. 



Shell small, thin, elongate-triagonal, convex, somewhat inflated ; 

 umbones anterior, turning slightly toward the posterior end; shell 

 rounded before, much elongated behind, the posterior length about 

 twice the anterior. It is furnished with very fine, distinct, con- 



5. Ralph Arnold's description ; California Academy of Science, voL III, p. 96. 



