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Fio. is;. TeUinopsu sub-emarginata. Two valves, showing variation in size and 

 form (from Hall). 



Found in the Strophalosia bed, in Avery's Creek, and the 

 shale just above it ( very rare). 



Genus PHOLADELLA. Hall. 



[Ety. : Diminutive of the modern genus Pholas.] 

 (1870: Preliminary Notice Lamellibranchiata, 2, p. 63 i 



Shells with equal inequilateral valves, elongated, varying 

 in outline. Anterior end rounded or obliquely truncate; 

 posterior end truncate. Incurved anterior beaks: straight 

 cardinal line; prominent rounded or sub-angular umbonal 

 slopes; a deep, sharply -defined lunule; a well-marked 

 escutcheon ; concentric striae and undulations, and distinct 

 radii, covering all but the anterior and cardinal slopes, — 

 mark this genus. 



Pholadella radiata. (Conrad.) (Fig. 188.) (Pal. 

 X. V., Vol. V., Pt. I., p. 469, Pis. LXXYIII., XCVI.) 



Distinguishing Characters. — Small size; cuneate outline; 

 regularly rounded basal margin ; obliquely to vertically 



Fio. 188. Pholadella radiata. Two right and two left valves (from Hall). 



truncate posterior end; anterior end obliquely truncate 

 above, by the deep lunule; cincture extending from beak to 

 base; fine concentric striae, and strong radii. 



Found ten feet below the Encrinal limestone, at Section 7; 

 in the Modiomorpha sub-alata bed, in Idlewood Ravine, and 

 on the Lake Shore. 



