NAPLES FAUNA IN WESTERN NEW YORK, PART 2 285 



common, the majority of specimens present a somewhat oblique condition. 

 The degree of this obliquity varies from the normal to the situation of the 

 beak at the posterior one third of the shell's length. It was such an 

 oblique shell that was figured by Hall in 1843 (op. cit?) as L u c i na ? 

 r e t u s a. 



This obliquity is apparently not accidental or due to distortion from 

 compression ; occasional specimens show the young shell, outlined by a 

 deep growth furrow, to be orbicular ; the obliquity of the shell which com- 

 mences soon thereafter is a result of natural growth. 



Had we but a few specimens of this species under study, there might 

 seem some justification for regarding these oblique shells as a persistent 

 variety ; but, among the several hundred shells before us, it is evident that 

 the passage from the erect to the oblique form is quite as gradual as from 

 the nonstriate to the striate shells. 



Only this extensive material has served to demonstrate the protean 

 character of this species, to which in all its various expressions we can 

 apply but one term. 



In some of its aspects the species very closely approaches the well 

 known Cardiola concentrica von Buch, a widespread Intumescens 

 zone organism throughout European outcrops. Guided by Beushausen's 

 excellent figures and full description of this shell, we observe that in none 

 of the examples of O. suborbicularis are the cardinal plications so 

 strongly developed, nor is it often that the surface of this shell is so 

 strongly and regularly corrugated as that. Von Buch regarded his species 

 as bearing radial striae, but Beushausen states he could find only the barest 

 traces of such lines, and suggests that they belong to the inner shell layers. 

 Though we find among the Portage shells those that we regard as typical 

 examples of C. concentrica, yet these appear not to have entered the 

 Naples subprovince. We may safely infer that, with its wide range of 

 variation, O. suborbicularis is, thus, a species comprehending a local 

 expression of C. concentrica. Beushausen expresses the opinion 

 that Hall's Edmondia? tenuistriata is C. concentrica, and, 



