REPORT OF THE STATE PALEONTOLOGIST I903 255 



I beak. The average shell measures 14111111 by 14mm by 6mm. The 

 pedicle valve is convex, specially in the middle tov^ard the beak. 

 The brachial valve is most convex at the beak. One or two strong, 

 concentric growth lines are usually present on each valve. 



N". elegans Hall 

 Quite abundant in the Becraft and Lower Oriskany. A shell 

 (.slightly above the average in size measures 15mm by 17mm by 8mm 

 [in length, breadth and thickness respectively. 



N. ventricosa Hall 



Rather poorly preserved and not abundantly represented in the 



^Coeymans. 



Meristella laevis (Vanuxem) 



One of the most abundant Helderbergian species, occurring usu- 

 ally as perfect shells but often as internal molds. It is very abundant 



1 



[from the Coeymans to the Becraft inclusive. 



M. lata Hall 

 Very abundant, specially in the Upper Oriskany. It occurs as 

 ' frequently in the form of internal molds as in that of perfect shells. 

 In a large shell of this species, the length of the striated portion of 

 the internal mold of the muscle impress was 27mm. This was the 

 largest specimen found. This species is also present in the Port 

 Ewen. 



I The Meristella sp. of the Upper New Scotland L2 and L3 

 I is a shell alrhost as broad as M. lata. 



M. princeps Hall 

 ! Few specimens found but usually well preserved. One specimen 

 was noted in the Lower New Scotland and several in the Becraft. 



PELECYPODA 



Pterlnea? gebhardi (Conrad) var. 

 j One large specimen from the Upper Oriskany agrees with this 

 I species in size and in the broad and not prominent radiating ribs. 

 \ The grooves between the ribs have comparatively faint and narrow 

 \ rays. The ribs themselves are very broad and are longitudinally 

 striated, while the whole shell has rather faint concentric ridges. 



