120 PALAEONTOLOGY OF ILLINOIS. 



Length from beak to base 1 3 / 16 inches ; greatest breadth ! 5 /i 6 

 inches; length of anterior ear % inch. 



Position and locality : From the upper division of the Keokuk 

 limestone, Warsaw, 111. 



Collector, A. H. Worthen. 



No. 2511 of the Illinois State Museum. 



AVICULOPECTEN MENARDi. Worthen, 



PL XXII. Fig. 12. 



Lima? menardi, Worthen, March, 1884. Bulletin No. 2, of the Illinois State Museum of 



Natural History, page 22. 



Shell small, thin, obliquely ovate, very inequilateral ; ears small, 

 nearly equal in size, triangular; hinge line straight, and about 

 half as long as the greatest width of the shell. Right valve 

 nearly flat; anterior side projecting forward, with a nearly 

 straight margin to the regular curve of the basal margin; pos- 

 terior side shorter than the anterior, and rounding up from the 

 basal margin nearly to the ear, where it makes a slight back- 

 ward curve, forming a slight sinus just below the ear. 



Surface marked by numerous transverse stria?, that extend 

 from the hinge line quite around the borders of the shell, cover- 

 ing apparently its entire surface. Left valve unknown. 



Length from the hinge line to the basal margin, % inch ; great- 

 est breadth about the same; length of the hinge line % inch. 



The only specimen of this pretty shell in the State collection, 

 was obtained from the bituminous shale forming the roof of the 

 Greenview coal in Menard county. 



Collector, A. H. Worthen. 



No. 2513 of the Illinois State Museum. 



GENUS LIMA, Bruguiere. 

 LIMA CHESTERENSIS. (sp. nov.) 



PI. XXII, Fig. 7. ' 



A single valve of a shell belonging apparently to the genus 

 Lima was obtained by the Avriter from a thin layer of ferru- 

 ginous limestone intercalated in the shales which separate the 

 main limestones at Chester. The specimen represents the right 

 valve with the posterior ear broken away. 



