154 NEW YORK STATE MUSEUM 



some obscure wrinkles on the dorsum which diverge from the keel forwards and outwards, 

 forming with the keel an angle of about 45°. Transverse diameter of the aperture of a 

 large specimen, eighteen lines ; vertical diameter (from the dorsal side of the aperture to 

 the opposite side of the shell) about the same. 



This is a shell often attaining large size, sufficiently common but sel^ 

 dom found except as internal casts. Its stoma is much more explanate than 

 was indicated by Billings's imperfect figures and as the shell is apparently 

 seamless it appertains to the group of species represented by B. p a t u 1 u s 

 Hall and B. forbesi Clarke of the Lower Devonic. The mature forms 

 display no external ornament except traces of concentric lines, but young 

 shells, some of which have been preserved as silicious replacements, carry a 

 series of elevated revolving lines. 



Localities. In the shore outcrops at Grande Greve. Billings's specimen 

 was from Indian Cove. 



Bellerophon (Plectonotus ?) gaspensis nov. 



Plate 17, figures 17, 18 



Shell rotuloid, rapidly expanding ; expanded but not explanate at the 

 aperture. Outer surface trilobed by two revolving lateral furrows which 

 start early and become wider and deeper with age. These do not divide 

 the surface equally but the lateral divisions are considerably narrower than 

 the median division which is broad, prominent and elevated but flattened 

 on top and may have had a peripheral seam. The specimen measures 12 

 mm in diameter and has about the same apertural width. 



Species of this type are well distributed throughout the early Devonic 

 and we may cite, P. derby i and P. salteri Clarke from the River 

 Maecuru, Brazil, and the so called Bell, trilobatus from the Spiriferen 

 sandstone of Germany. 



Locality. Grande Greve. The shell appears to be rare, a few ex- 

 amples only having been observed. 



PELECYPODA 

 Aviculopecten jumeaui nov. 



Plate 19, figures 4, 5 



Shell of considerable size, suberect, explanate below, with suborblcular 

 outline tending to obliquity posteriorly. Beak anterior, anterior wing 

 short, posterior broad flat or subconcave, the point not extending beyond 

 the posterior curve of the shell ; sharply incurved on the lateral margin of 

 the shell where that is straight, and oblique to the outer curvature. Sur- 

 face with fasciculate bands somewhat after the type of ornament in 

 Actinopteria textilis; coarse distant ribs with intermediate smooth 

 spaces divided by a simple low rib, these interspaces being subdivided near 



