566 PALiEONTOLOGlCAL REPORT OF GEOLOGICAL SURVEY. 



A description of some of the most characteristic shells, of the principal 

 coal seams in the western basin of Kentucky, by E. T. Cox, Assistant 

 Geologist. 



PECTEN PROVIDENCESIS. Cox. 

 (Plate VIII. fig. 1, left valve natural size.) 



Semi-circular; as broad as high; nearly equilateral; left valve slight- 

 ly convex; about thirty-three broad prominent ribs, of unequal width, 

 and irregularly fluted; radiate from the beak to the circumference; 

 crossed below the disk by two well defined bands, marking stages of 

 growth. Anterior ear of the valve under description is wanting, but 

 that of the right valve beneath, is in part exposed, finely ribbed, and 

 crossed by concentric bands; inferior ear finely ribbed, crossed by 

 fimbriating folds, curved outward from the beak. Rostral angle 95° ; 

 height 3.-^-0 inches; width B.^\ inches. Its size and broad fluted 

 ribs renders it easily distinguished from other species. 



Position and locality. Found by the topographical assistant, Sidney 

 S. Lyon, in the limestone which overlays the main coal, No. 11, at 

 the town of Providence, Hopkins county, Kentucky. Fragments are 

 somewhat numerous, but it, is difficult to obtain them in as perfect a 

 6tate of preservation as the one figured. 



LOXONEMA REGTJLARIS. Cox. 

 (P. VIII, fig. 2, natural iize.) 



Elongated; acutely conical; volutions ten; regularly enlarging; con- 

 vex; covered with fine transverse striae; convex in the direction of the 

 spire; sigmoidal on the last whorl; suture small, slightly impressed; 

 body whorl about one half the whole length; colamella lip elongated, 

 slightly reflected; outer lip thin; mouth about twice as long as broad; 

 spiral angle 35°; length 2.-jW inches; width .Jfa inch. 



It most nearly resembles L. Haiti, Norwood and Patten, Jour. Acad. 

 Nat. Sci. June, 1855, but differs in being larger, less acute, and more 

 convex on the volutions. It was found by Sidney S. Lyon, Topo- 

 graphical Assistant, and is converted into pyrites of a bright yellow 

 color and metallic lustre, and is in a fine state of preservation. 



