EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA Jl 



Aviculopecten flammiger Clarke 



Plate ij, figures 1-4 



Aviculopecten flammiger Clarke. N. Y. State Mus. Bui. 107. 1907. p. 196 



A shell of somewhat variable exterior which approaches in out- 

 line the Pterinopecten pro tens Clarke of the Becraft Mountain 

 Oriskany [see N. Y. State Mus. Mem. 3, p. 32, pi. 4, fig. 7], but it is unlike 

 that in exterior. The round subcircular shell is strongly radiated, the pri- 

 mary radii being sometimes coarse with broad fascicles of intermediate 

 striae, sometimes finer and less distinctly fasciculate. In the number of 

 these primary ribs there is the greatest variation. All are crossed by sharply 

 elevated concentric striae. The anterior wing is deeply silicate and sinuous, 

 the posterior relatively large and with concentric striae only. Only left 

 valves of this species have been observed and they are readily recognized 

 in spite of their variable ornament. 



Locality. Askwith siding, Canadian Pacific Railway ; Misery stream, at 

 the first dam in the town of Sandwich ; Moose river on the north bank and 

 along Stony creek ; near Blind Cove point, Telos lake, Me. 



Pterinea mainensis Clarke 



Plate 14, figures 3-7 



Pterinea mainensis Clarke. N. Y. State Mus. Bui. 107. 1907. p. 201 



Shell often of large size, oblique, hinge considerably shorter than the 

 full length of the valve. Anterior wing well developed, but slightly sloping 

 at the hinge and set off from the shell body by a low broad sulcus. Poste- 

 rior wing relatively short not reaching the posterolateral limit of the valve 

 and sometimes not more than one half or two thirds this distance. Body 

 of the valves depressed, not sharply set off from the wings ; anterior out- 

 line at first direct, then inclining more or less rapidly backward and often 

 extended at the posterolateral margin from which the retreat toward the 

 posterior wing is abruptly oblique. The surface of the left valve is 

 covered by fine radii, equal on the anterior slope but unequal on the 

 posterior and showing a tendency to fasciculation. These are minutely 

 cancellated by concentric lines which on the anterior slope and wing 

 and on the posterior slope become prominent to the exclusion of the 

 radii. The right valve is shallow, evenly depressed, with the radii 

 along the crescence line stronger and more distant and the cancellating 

 lines subdued. 



The hinge is distinctly pterineoid, showing a doubly divided umbonal 

 tooth, strong oblique posterior ridge and broad, striated ligament 

 surface. 



