84 PROCEEDINGS OF THE NATIONAL MUSEUM voi. 78 



in Indiana, is yet occasionally observed in American species of the 

 genus (for instance, /. labiosa). 



Occurrence. — The type specimen is said to be an "impression of the 

 outside of a small (right) valve" one-eighth of an inch in length and 

 but slightly convex, found in the basal part of the Llandeilo Flags 

 of South Wales, at Upper Solva, Solva Harbour, St. Davids. Hicks 

 subsequently gives the horizon as the Menevian Paradoxides bed. 



INDIANA? CAMBRENSIS (Hicks) 



Plate 9, Figure 18 



Leperditia cambrensis Hicks, Quart. Journ. Geol. Soc. London, vol. 27, 1871, 

 p. 401, pi. 15, figs. 15-17. — Etheridge, Mem. Geol. Surv. Gt. Britain, vol., 

 ed. 2, 1881, p. 487. 



This species is removed from Leperditia to Indiana for reasons 

 practically the same as those inducing a similar coiu'se with respect 

 to L. solvensis Jones. As in that case, the species is known only 

 from poor figures and quite inadequate remarks. The specimens are 

 said to much distorted by pressure, and the figures (reproduced on 

 Plate 9) vary so greatly that, with the evidence now available, it is 

 impossible to decide as to the specific relations of the species. Jones, 

 who saw the specimens, regarded them "as undeterminable." ^ If 

 figure 15 is approximately like the normal form it would be a close 

 ally of /. lippa. The other two specimens are probably of a different 

 type. Both recall another Cambrian species from the same locality 

 subsequently described by Jones as Leperditia hicksii. The latter is 

 here referred tentatively to Bradoria. 



Occurrence. — Red shales in lower part of the "Longmynd group," 

 Lower or Middle Cambrian, St. Davids, South Wales. 



INDIANA LENTIFORMIS (Cobbold) 



Plate 9, Figure 30 



Leperditia? lentiformis Cobbold, Quart. Journ. Geol. Soc, vol. 96, 1921, p. 367, 

 pi. 24, figs. 46 a-c. 



Diagnosis. — General outline bean shaped; anterior end shortl}* 

 truncate; dorsal border gently convex for about two-thirds of the 

 total length, then bending more rapidly and passing to the posterior 

 rounded end in a line that is almost straight; ventral border one long 

 fairly regular curve from the truncate anterior to the posterior end; 

 surfaces of both valves regularly convex, except near the anterior 

 end, where there is a short ill-defined depression passing obliquely 

 towards the ventral border; test thin, corneous, having the surface 

 marked by a network of impressed lines, the interspaces being con- 

 vex, and more or less elongate and parallel with the border. 



8 Quart. Journ. Geol. Soc. London, vol. 28, 1872, p. 1S4. 



