576 PAL^IOfJTOLOaiOAL REPORT OF GEOLOGICAL SURVEY - 



sis and i\£ ferratus. Nolin iron works, Edmondson county, Ken- 

 tucky. 



LINGULA TJMBONATA. Cox. 

 (PI. X, fig. 4, entering valve enlarged; fig. 4 a, natural size.) 



Subpentagonal, longitundinally elongated, very tumid at the umbo ; 

 beak elevated, pointed, not projecting beyond the cardinal border; 

 greatest width about one- third the length below the beak; sides nearly 

 parallel, slightly convex and narrowing towards the front ; front very 

 obtusely rounded, posterior lateral margins rather acutely rounded, 

 uniting in an elliptical point at the beak; slightly flattened along the 

 mesial line, commencing from a point near the beak, and gradually 

 widening to the front margin, a little pinched in near the umbo ; sur- 

 face beautifully marked with fine concentric, strise between the more 

 distinct lines of growth ; length .jW °f an i ncn > width -^~ of an 

 inch. 



This species is easily recognized in well preserved specimens, by 

 its prominent umbo, and its peculiar longitudinally flattened mesial 

 area. It attains a much greater size, but we have none larger suffi- 

 ciently perfect to figure. 



It is highly characteristic of No. 1, B, coal, and has been found in 

 beds of this level, by Mr. Lesquereux, in Ohio and Pennsylvania. 



Position and locality. Very abundant in the black slate roof of No. 

 1, B, coal, at Bell's mines, Crittenden county ; Casey's mines, Union 

 county, and Hawesville mines, Hancock county, Kentucky. 



