LOWER CARBONIFEROUS FOSSILS. 571 



Formation and locality : Madison limestone, Crowfoot Ridge, Gallatin 

 Range, bed 28; J. P. Iddings and W. H. Weed. Same, top of bed 24; J. P. 

 Iddings. Keokuk to Kaskaskia; Europe; Mississippi Valley; White Pine 

 and Eureka districts, Nevada; Salt Lake City, etc., Utah; Lake Valley 

 mining district, etc., New Mexico; Lake County, Colorado; Guatemala; 

 Bomjardin and Itaituba, Brazil. 



CONOCARDIUM Broun, 1835. 



Conocardium pulchellum White and Whitfield (?) 



PL LXVI, fig. 14a. 



Conocardium pulchellum White and Whitfield, 1802: Proc. Boston Soc. Nat. Hist., 

 Vol. VIII, p. 299. 



In the absence of identified material I am not sure that the reference 

 to White and Whitfield's species is correct, for I have but a single specimen, 

 so that it is impossible to determine the range and normal expression of the 

 shell; while C. pulchellum has not been figured, at least by its authors; and 

 a description unaccompanied by illustrations, especially in this genus, is 

 almost sure to be unsatisfactory. 



My shell is small, not veiy convex. Truncation of the anterior margin 

 slightly concave, nearly the same length as the straight hinge line, which 

 it meets at an obtuse angle. Posterior cardinal angle rounded. Ventral 

 margin sloping and curving from the posterior angle to the anterior trunca- 

 tion. Posterior wing somewhat flattened and concentrically rugose. Sur- 

 face otherwise marked by about twenty-five radiating stria;, which are 

 strong and abrupt, leaving between them spaces greater than their own 

 diameter. Length along the hinge line, 6.5 mm.; greatest diameter (from 

 posterior cadinal angle to the junction of the ventral margin with the 

 anterior truncation), 12.5 mm. 



This species seems to have some points of resemblance with C. napo- 

 leonense Winchell, but it is nearer White and Whitfield's form. 



C. A. White 1 has proposed the name Conocardium semiplenum for a form 

 from the same region as that under consideration. It belongs likewise to 

 the same type of shell, as comparisons are made with C. trigonale Hall, 

 which C. pulchellum also resembles. It is not improbable that he may have 



'U. S. Geol. Surv. W. 100th Meridian, Vol. IV, 1877, p. 94. 



