189G.] 247 [Smith. 



C. A. White (loc cit.), from the Permian of Texas. No analogous form 

 was found in the true Coal Measures of Texas, which is not at all sur- 

 prising, since their fauna is so little known. In the Upper Carboniferous* 

 beds of Scott county, Arkansas, 1 N., 28 W., section 4, northeast quarter 

 'of southeast quarter, was found a single specimen that agrees perfectlj' 

 with the PUuroi^horiis of Dr. White. It is nothing unusual to find a 

 Permian species in the Carboniferous, but the identification is uncertain, 

 owing to the poor preservation of Dr. White's original and of the 

 Arkansas specimen. 



Genus Conocardium Bronn. ConocarcUum aliforme Sowerby, sp., PI. 

 xxii, Figs. 1 and 2. Cardium aliforme Sowerby, Miii. Conch., Vol. 

 vi, p. 100, Table 552, Fig. 2. Conocardium aliforme Sowerby, sp., 

 Bronn, Leth. Geocjii., i, p. 420, PI. iii. Fig. 9. Pleurorhynchus mi- 

 nax Phillips, Geol. of Yorkshire, p. 210, PI. t. Fig. 27. 



This genus is rare in the American Carboniferous, and especially so 

 in the Coal Measures, being represented there by only two other species, 

 C. ohUqvum Meek and Wortheu, Geol. Surv. Illinois, Vol. vi, p. 529, and 

 C. parrisld Worthen, Geol. Surv. Illinois, Vol. viii, p. 112. The former 

 is more nearly related to C. aliforme, but difi"ers from it in its much 

 smaller size, greater obliquity of the shell, and shorter hinge line. The 

 surface of C. oliquum is marked by narrow radiating ribs, while those of 

 C. aliforme are wider tlian the depressions between them. 



The intermediate spaces are occupied by a secondary rib only on the 

 rounded anterior side of C. aliforme, while the same thing occurs even 

 on the posterior side of C. ohliqimm. C. aliforme also has the hinge 

 line longer, and the space between the incurved beaks wider ; also the 

 ribs on the anterior cordate space are much finer, and this area is 

 bounded by a rather distinct carina, being slightly concave near the 

 rounded border, and rising toward the anterior rostrum, which is pre- 

 served on some of our specimens. Tlie shell has its greatest convexitj^ 

 at the anterior end, wliere tlie broad carina cuts off the cordate area. 

 Behind this is a distinct furrow, Avhich shades off into the posterior com- 

 pression of the shell, and dies out in a gentle curve toward the rounded 

 gaping margin. Tlie ribs are broader and the concentric growth lines 

 more distinct towards the posterior end. The concentric lines are not 

 visible on the cordate area. The posterior portion of the shell, next to 

 the hinge line, is not ribbed, but marlied with fine, radial lines. 



Goldfuss, in PetHfacta Germaniw, Part ii, p. 203, PI. cxlii, Fig. 1. 

 describes and figures Conocardium aliforme, but according to McCoyf 

 he has confused two species, one of which is a Devonian species from 

 the Eifel. The true 0. aliforme is that described by Phillips, Geol. of 

 Yorkshire, Vol. ii, p. 210, PI. v, Fig. 2, as Pleurorhynchus minax, of the 

 Carboniferous Limestone, and by Goldfuss, PI. cxlii, Fig. 1, e, f, h, i, I, 



*By the stratigraphy these beds are Barren Coal Measures, but the fossils sh ow close 

 relations to the Tipper Coal Measures, 

 t British Palseozoic Fossils, p. 517. 



