474 CRETACEOUS PALEONTOLOGt. 



large as that species and its surface markings are quite distinct as 

 has already been pointed out under the discussion of that species. 

 The species is more typically represented in the fauna of the 

 Woodbury clay, from which formation, near Haddonfield, Con- 

 rad's type specimens were obtained, but it also occurs in the 

 Merchantville clay-marl and in the Navesink marl. The Wood- 

 bury specimens seem always to be proportionately higher and 

 narrower than P. burlingtonensiSj but in the Merchantville and 

 Navesink formations, individuals are not infrequently met with . 

 having nearly the proportions of that species ; they can always be 

 distinguished, however, by their surface markings and by the less 

 nearly equal size of the auriculations. It is possible that these 

 rounder, Merchantville and Navesink specimens should be sepa- 

 rated as a distinct species, characterized not only by their different 

 form, but also by the larger size which they often attain. 



Formation and locality. — Merchantville clay-marl, near Mat- 

 awan (loi), near Jamesburg (139), Lenola (163); Woodbury 

 clay, Ivorillard (102), Haddonfield (183); Marshalltown clay- 

 marl, near Swedesboro (179); Wenonah sand, near Marlboro 

 (130) ; Navesink marl, Crosswicks Creek (149, 147*), Freehold 

 (Whitfield). 



Geographic distribution.- — New Jersey, Mississippi, Texas. 



Pecten conradi (Whitfield). 

 Plate L., Figs. 1-4. 



1868. Pecten simplicus Con., Cook's Geol. N. J., p. 725 (not 



Pecten simplicius Con., Jour. Acad. Nat. Sci. Phil., 

 2nd ser., vol. 4, pp. 283-284, pi. 46, fig. 44.) 



1869. Sinsyclonema ? simplica Con., Am. Jour. Conch., vol. 



5, p. 99, pi. 9, fig. 20. 

 1886. Amusium Conradi Whitf., Pal. N. J., vol. i (Monog. 



U. S. G. S., vol. 9), p. 52, pi. 7, figs. 8-10. 

 1905. Pecten conradi Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 12. 



Description. — ^"Shell small, seldom exceeding half an inch in 

 height ; erect-ovate, becoming more elongate proportionally with 



