EXPI^ANATION DF PLATl'. Xf.lX, 



Pectex akcii.i.ensis Ciiiira'l p. 472 



1-2. \'ic\\s cif iwi) ncarl}- circulai" individuals illustrated b\" 

 WhitficlJ. 



Nat'csink marl; I'rcchold. 

 3-4. Views of tw'i individual valves iif nunnal fijrui and size. 

 Internal casts. 



H'lioJIuiry ilay : I,iiiillard_ iiiu). 



PECTEX liURLINTOXENSIS Cklljll, p. 47O 



5. A large internal cast of a single valve. 



5. A small single valve <>( the form called P. pcrlaiiicUosiis 

 by Whitfield. 



M L-rclumlz'ilIc cluy-iiiarl : ncai' Malaz^'uii . (loi). 

 7-8. A cast of the interior and the natural impression of the 

 e.xterior of a single \'alve. 



McrchafitviUc clay-marl ; Lcin'Ia. {163). 

 9. A large internal cast of a single valve. 



Woodbury clay; Lorillard, (102). 



Pecten sp. 



10. View of an internal cast. 



Maiiastjiiaji marl; farmiiigdalc, (/JtV), 



980 



