Marilakd Geological Suisvey 615 



BucHiOLA COKVERSA Clarke 

 Plate LX, Figs. 4-6 

 Buchiola conversa Clarke, N. Y. State Mus., Mem. vi, p. 300, pL x, fig. 22, 1904. 



Description. — This species is smaller than the average of B. retro- 

 striata and has a more circular outline. While it has about the same 

 number of ribs as that species, 12-15, these are extremely fine and 

 though flat at the start become highly concave over the body of the shell 

 by the elevation of the lateral margins into linear ridges. As the fur- 

 rows between the ribs have about the same width the shell may present 

 the appearance of bearing double the number of ribs ascribed to it, each 

 rib assuming a duplicate appearance due to the depth of its surface de- 

 pression. Only t!ie faintest trace of concentric markings is to be dis- 

 covered. 



The peculiar surface characters render it quite easy of separation from 

 its associates in the same genus, but we find that this style of ornament 

 is approached by some of the forms assigned to tlie genus Faracardium 

 {e. g., P. dupJicnlum Clarke, Xaples fauna of Xew York) and serves to 

 indicate the quite conventional value of the latter genus. 



Length G mm. ; height 5 mm. 



The typical specimens of this species are from the lower beds of the 

 Naples shales in New York north of Portageville in the Genesee Valley 

 and a figure of the type specimen is here given. 



Occurrence. — Jennings Forjiation, Woodjiont Member, Naples 

 Fauna. Polish Mountain section on the National Eoad east of Gilpin- 

 town. 



Collection. — Maryland Geological Survey. 



Buchiola mari.^ n. sp.' 



Plate LX, Figs. 7, 8 



Description. — This species will be found to differ from other repre- 

 sentatives of the genus in the following particulars : It has the size and 

 form oF //. retruslriutu but carries fully 20 ribs, all sharply elevated 



' See Clarke, N. Y. State Mus., Mem. vi, p. 212, 1904. 



