EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 25 



Opercula of Gastropods (Euomphalus ?) 



Plate i, figures 10-12 



Associated with the gastropods described are discoid bodies having the 

 aspect of large Orbiculoideas, with an apparently concentric surface linea- 

 tion, and a considerable thickness of substance. 



The markings on these are really close wound spirals beginning at a 

 central or subcentral apex. The bodies are sometimes flat from compres- 

 sion, but usually convex and have an aspect similar to these which by Whit- 

 eaves, Lindstroem and Spitz have been looked upon as opercles. 1 



Horizon. No. 1 1. 



Pterinopecten denysi Clarke 



Plate 3, figure 7 



Pterinopecten denysi Clarke. N. Y. State Mas. Bui. 107. 1907. p. 199 



Shell moderately large, subcircular, known only from its left valve which 

 in the single specimen before us is somewhat incomplete about the hinge 

 but has a very characteristic sculpture. This consists primarily of a few 

 strong radial ribs of unequal size, which rapidly spread apart leaving broad 

 interspaces which do not, in any noticeable degree on the body of the shell, 

 become occupied by other ribs, except small and simple ones of a secondary 

 series. The primary ribs themselves widen, become broad and flat and split 

 up into lesser ones, though all derived from the division of any rib may 

 remain together in a fascicle. On the anterior part of the shell the diffusion 

 of the riblets is less defined and regular. All these are crossed by very fine 

 reticulating concentric striae. This is a style of irregular sculpture which 

 with more specimens would probably prove to be quite inconstant and is in 

 a measure reproduced in the very variable species from the Oriskany of 

 New York, which we have designated as P. pro tens. A similar aspect 

 is presented by the P. wulfi Freeh from the lower Coblentzian of the 

 Eifel. 2 



Species name. Nicholas Denys, in 1672 proprietor of all the country 

 from Cape Canso to Cape Rosier. 



Horizon. No. 9. 



'See e. g. Whiteaves. Palaeozoic Fossils. 1884. 3: 33, pi. 3, fig. 10, n ; pi. 7, fig. 7. 

 2 Devon. Aviculiden Deutschlands, p. 25, pi. 2, fig. 7. 



