279 



fine concentric stri;e; band limited by linear carina on either 

 side, the concentric stri;e making an abrnpt retral curve 

 within. 



Found in the rieurodict3'um beds, chiefly as casts. 



Fleurotomaria itvs, var. tenuisjnra, Hall, differs in the 

 greater number of volutions (sev^en or more); greater ro- 

 tundity of the last two volutions; strong revolving stride, 

 coarser crenulations, and absence of revolving carina limit- 

 ing the "band." 



Found "in the shales of the Hamilton group, at Hamburg, 

 shore of Lake Erie."" ( Hall, type. ) 



Plelkotomakia ( Ai'iLLAiMA. Courad. (Fig. 2()*.>.) i Pal. 

 N. Y., Vol. v., Pt. H., 1). 77. PI. 

 XX.) 



Distill (xuishiiiii- Characters. — Tur- 

 reted s])ire, with fom* or moi-e volu- 

 tions, ra])idly increasing in size; 

 ventricose body-whorl, an angular- 

 ity on its upper side caused by two 

 or three prominent revolving ca- 

 rime; revolving and concentric 

 sti'i;e. 



Found in the Strophalosia bed, on the Lake Shore 

 (rare). 



PlEUIJOTOMARIA I'LAMDORSALIS. Hall. (Fig. 210.) (Pal. 



N. Y., Vol. Y., Pt. n., p. 82, PI. 

 XXL) 



Distinguish iiig Characters. — De- 

 pressed trochiform, sub-discoidal 

 spire ; sub-angular volutions, 

 rounded below ; aperture straight 

 on upper side, somewhat rounded 

 below; strong revolving carina, 

 two-thirds distant from suture to 

 peripheral band; similar carina on 

 the lower side; simple band; ^;::;^^X\^S^^^^^^^'^ 



strong concentric Striie. obliterated (after Hall 



Fig. 209. Pleitrotoiuaria cajiil- 

 litn'a (after Hall). 



Fig. 210. Plenrotomaria pluni- 



