104 University Geological Survey of Kansas. 



valve, so as to cause some appearance of an obscure mesial sinus, 

 but without producing any corresponding mesial elevation on 

 the other valve, or visibly inturrupting the general straightness 

 of the uniting margins of the two valves ; lines of growth ob- 

 scure ; punctures visible under a good pocket lens, and very 

 regularly disposed." Measurements : Length, 10 mm. ; width, 

 8 mm. ; convexity, 7 mm. 



Range and distribution : Upper Coal Measures ; Fort Scott, 

 Tola, Kansas City, Lawrence, Lecompton, Topeka, Beaumont. 



CLEIOTHYRIS, 



King: (non Phillips), Mon. Perm. Foss., Pal. Soc, p. 137, (1850). 

 Hall and Clarke. Pal. N. Y., VIII, pt. II, p. 90, ( 1893) ; etc. 



Cleiothyris roissyi. Plate XII, fig, 2; plate XI, figs. 5-5c. 



Spirifer de roissyi L'Eveille, Mem. Soc. Geol. de France, n, p. 39, pi. n, 



ff. 18-29, (1835). 

 Terbratida roysii Marcou, Geol. N. Amer., p. 51, pi. vi, f. 10, (1858). 

 Athyris sublamellosa Hall, Geol. Surv. Iowa, i, pt. n, p. 702, pi. xxyn, 



f. 1, (1858); etc. 

 Athyris parvirostris Meek and Worthen, Proc. Acad. Nat. Sci. Phil.. 



1860, p. 451. 

 Spirigera americana Swallow, Trans. St. L. Acad. Sci., n, p. 89, (1863). 

 Spirigera pectenifera Swallow (non Sowerby), ibid., p. 88. 

 Athyris planosulcata Geinitz (non Phillips), Carb. u. Dyas in Neb., p. 42, 



(1866); etc. 

 Spirigera planosulcata? White, Wheeler's Rep. Geog. Expl. Surv. West 



100 Mer., iv, p. 257, pi. iv, ff. 10, 11, (1877). 

 Athyris hirsuta Walcott, Mon. U. S. Geol. Surv., viii, p. 222, pi. xviii, f. 5, 



(1884). 

 Cleiothyris royssii Hall and Clarke, Pal. N. Y., viii, pt. n, p. 91, pi. xlvi, 



ff. 23, 24, pi. lxxxiv, f. 32, (1893). 

 Cleiothyris sublamellosa Hall and Clarke, ibid., p. 91. 



Meek and Worthen's description: " Shell of medium size, 

 quadrato-subcircular, moderately gibbous, length and breadth 

 nearly equal, sometimes a little wider than long (other ex- 

 amples a little longer than wide) ; greatest convexity at the 

 middle ; valves equally gibbous ; lateral margins usually promi- 

 nent, and narrowly rounded in outline at the middle, thence 

 converging with a slightly convex outline to the faintly sub- 

 truncate front ; posterolateral margins a little inflected, so as 

 to form slight concavities, converging to the beaks at an angle 

 of about ninety-seven degrees. Both valves destitute of a mesial 



