592 SYSTEMATIC PALEONTOLOGY 



Pecten venustus Conrad, 1868, Cook's Geol. of New Jersey, p. 725. 



Pecten venustus Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 45, pi. 



vii, figs. 1, 2. 



Pecten venustus Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 11. 

 Pecten venustus Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, p. 



478, pi. li, figs. 1-5. 



Description. " Shell thin, depressed, about half an inch in diameter, 

 with fifteen or twenty double costae; those on the lower valve delicately 

 beaded. From New Jersey." Morton, 1833. 



Shell small, rarely more than a centimeter and a half in diameter, more 

 than moderately inflated, subequilateral excepting for the auricles, a little 

 higher than wide, dorsal margins converging at an angle of approxi- 

 mately 90, lateral ventral margins roughly subscribing the major portion 

 of a circle; external surface sculptured with some fifteen radial costae 

 broader toward the ventral margin and for the most part medially sulcate, 

 interradials deeply channeled, usually narrower than radial s; auricles 

 unequal, the posterior smooth and rudimentary, the anterior narrow, elon- 

 gate, distally truncate, sculptured with four or five subequal lirae ; byssal 

 notch rather shallow; interior plicated in harmony with the eternaxl 

 sculpture. 



Pecten venustus Conrad is the only one of the small Pectens that 

 develops a vigorous radial sculpture. 



Occurrence. MATAWAN FORMATION. Post 236, Camp Fox, Post 218 

 and Post 192, Camp U & I, Chesapeake and Delaware Canal, Delaware. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, U. S. National Museum. 



Outside Distribution. Matawan Formation. Marshalltown clay marl, 

 New Jersey. Monmouth Formation. Navesink marl, Eed Bank sand and 

 Tinton beds, New Jersey. Ripley Formation. Exogyra costata zone, 

 Chickasaw and Union counties, Mississippi. Selma Chalk. Exogyra cos- 

 tata zone, Sumter County, Alabama ; east-central Mississippi. 



PECTEN CLIFFWOODENSIS Weller 



Pecten cliffwoodensis Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 

 iv, p. 469, pi. 1, figs. 7, 8. 



