73 



Avic. 



Aviculopecten carboniferus. {Carbonarius?) {Pecten 

 XIH,'^Bi^P^ ^®f]^P'_ carloniferus^ Stevens, Am. Jour. 



Sci. Vol. 25, 1858, page 261.) Col- 

 let's Indiana Rt. of 1883, page 144, 

 plate 28, fig. 5, left valve, natural 

 Ino(/^^ ^ ISS'S.^'^^^iil^Sg size ; fig. 6, right valve of another 

 individual. — XIII^ coal measures, at several places in Indiana. 

 (Note. — Probably the same as Swallow's Pecten Iroadheadi^ 

 upper coal measures of Missouri. No doubt the same as Geinitz's 

 Pecten hawni from Nebraska. Found also in New Mexico, 

 100th Med. Geol. Survey, Collett.) — In Pennsylvania, in the 

 Black fossilliferous limestone, 250' beneath the Pittsburgh coal, 

 in Fayette Co., F. Piatt in report L, p. 35; J. J. Stevenson, 

 KKK, p. 309. Also in Decker's Creek shale, under Mahoning 

 sandstone, Morgantown, W. Ya., Stevenson, in L, p. 36. Also 

 in Ferrif. L. Allegheny seiies, coal measures, Beaver Co. (Q. 

 62), Lawrence Co. (QQ, 47); Mercer Co. (QQQ, 25); and 

 Butler Co. (V, 147).— X77/, XIV, 



Aviculopecten convexus. {Pecten convexus.) Hall, 



vm^^ page 264, figs. 119, 6. VIII g. Chemung formation. 



3^^^p^ A species which cannot be mistaken by reason of its 



W~--^P unusual fatness or convexity, and the height of its 



H9^fflPv \^Q^^ above the hinge line. — VIII g. 



Aviculopecten dolabriformis. {Pecten dolahriformis ) 

 Hall, page 264, figs. 119, 4. — VIII g. Chemung 

 formation. It resembles Aviculopecten convexus ; 

 but its beak is closer to its hinge, its ears difi'erenTly 

 %j proportioned, hind ear very sharp, and the whole 

 shell more lopsided (oblique) and much flatter. 



Aviculopecten duplicatus. {Pecten duplicatus.) Hall, 



page 264, figs. 119, 2. VIII g. Chemung 

 formation. This species difi'ers from all 

 the other Chemung Aviculopectens in its 

 extraordinary breadth, and the doubling 

 of its radiating ribs towards the margin. 

 These ribs are plain towards the beak, and 

 cut up into squares by a system of con- 

 centric lines. They grow rough down- 

 wards towards the margin of the shell. — VIII g. 



