72 University Geological Survey of Kansas. 



The mesial septum is apparently short and thick. Two small, 

 sharp elevations mark the location of the double sinus on the 

 exterior. The adductor scars are located close beneath the 

 beak, oblique and ovate-elliptical in outline, and rather deeply 

 impressed. The pustules are arranged as in C. granulifer, ex- 

 cept that they are not always arranged in radiating rows 

 around the periphery, though they are in some specimens. 

 The interior of the dorsal valve is different from the rest of our 

 species. The sinus dividing the extremity of the deltidial proc- 

 ess splits into two, making the end of the process appear trifid. 

 The radiating ridges are nearly as in the preceding species, ex- 

 cept that the middle pair are recurved, forward and inward, 

 enclosing a depression resembling a muscular marking. The 

 mesial septum extends fully half the length of the shell, ending 

 in a slight enlargement. On either half of the valve, corre- 

 sponding to the folds of the other valve, are rather crescent- 

 shaped brachial areas, the outer edges of which are beset with 

 large, rather long, pustules. Pustules of the remainder of the 

 surface as in the other valve. In the anterior half of the shell 

 is a deep double sinus, enclosing a mesial fold, corresponding 

 to the sinus and fold of the ventral valve. 



Range and distribution : Lower Coal Measures ; Fort Scott 

 and Bronson, Bourbon county. 



The features which distinguish this species from the re- 

 mainder herein described are the mesial fold in the ventral 

 valve and the short hinge line. Its range is restricted to the 

 lower part of the Coal Measures. 



Chonetes verneuilianus. Plate IX, figs. 4-4c. 



Chonetes verneuilianus Norwood and Pratten, Jour. Acad. Nat. Sci. Phil., 

 in, p. 26, pi. ii, f. 6, (1854); Newberry, Ives' Rep. Col. Riv. of West, p. 

 128, (1861); Meek, Fin. Rep. U. S. Geol. Surv. Neb., p. 170, pi. i, f. 10, 

 (1872); Hall, 2d Rep. N. Y. St. Geol. pi. xlvii, ff. 20, 21, (1883); White, 

 13th Ann. Rep. St. Geol. Ind., p. 128, pi. xxv, ff. 7, 8, (1884): Hall and 

 Clarke, Pal. N. Y., vm, pt. i, pi. xvi, ff. 29, 21. 



Meek's description (in part) : li Shell rather small, varying 

 from subsemicircular to suboblong ; hinge line more or less 

 extended beyond the breadth of the valves at any other point ; 

 sometimes greatly produced. Ventral valve very convex, with 



