FOSSILS OF THE CAMBRIAN. 



19 



This species is unlike any described that is known to me. In general 

 form and surface characters it is allied to Kutorgina cingulata Billings, and is 

 undoubtedly of the same genus if the shells illustrated by figs. 8 and 10, on 

 page 8, of the "Paleozoic Fossils of Canada," vol. i, are taken as types. 

 The specific name is given in honor of Prof. R. P. Whitfield, the distin- 

 guished paleontologist. 



Formation and locality. Cambrian. Prospect Mountain Group, beneath 

 the Secret Cafion shale, on the west side of Secret Cation, Eureka District, 

 Nevada. 



Kutorgina Prospectensis, n. sp. 

 Plate ix, figs, la, b. 



Shell rather small for a species of the genus. It is thick and black, like 

 a linguloid shell. 



Ventral valve elevated, with the apex projecting over the triangular 

 area and extending considerably beyond the posterior margin; owing to 

 the exfoliation of the shell the extremity of the apex is unknown ; the sur- 

 face of the area is also unknown. Ventral valve depressed, slightly convex, 

 without a mesial sinus; marginal outline subcircular, with the posterior 

 margin obtusely angular at the beak; the beak is slightly depressed below 

 the highest point of the shell, and apparently projects a trifle beyond the 

 cardinal edge. Surface marked by strongly-defined fine concentric striae, 

 ten in a distance of one millimeter, where they terminate on the posterior 

 margin. 



The dorsal valve of this species is much like that of Iphidea Ldbrador- 

 icus Billings, but it does not appear to come within the limits of that genus 

 as defined by the type species. 



Formation and locality. Cambrian. In an arenaceous shale resting on 

 the Prospect Mountain quartzite, summit of Prospect Mountain, Eureka 

 District, Nevada. 



