PELECYPODA. 153 



1911. Actinopteria boydi Cleland, Wisconsin Geol. Nat. Hist. Surv., Bull. 21, pp. 



109-110, pi. 22, figs. 7,8. 

 1913. Actinopteria boydi Clarke and Swartz, Maryland Geol. Surv., Middle and 

 Upper Devonian, pp. 642-644, pi. 64, fig. 2. 



Hall's description — "Shell of medium size, rhomboidal; body ovate, varying in pro- 

 portions, the longitudinal axis at an angle with the hinge line of from 45° to 60°; length 

 varying from nearly equal to one-fourth greater than the height; margins regularly 

 rounded below, straight and nearly vertical for a short distance in front ; post-basal side 

 extended. 



Valves convex, the right valve a little less convex than the left. 



Hinge line straight from the anterior side of the beak to the posterior extremity. 



Beak anterior, acute, prominent, inclined forward, rising above the hinge in the left 

 valve. Umbonal region prominent, subtending an acute angle. 



Ear short, oblique, limited by a deep but not sharply defined sulcus. Wing large 

 triangular, not distinctly separated from the body of the shell ; margin concave ; extremity 

 acute. In the right valve the ear is somewhat more extended, the sulcus not strong, 

 but the byssal sinus is marked; the wing is proportionally larger and usually more acute 

 at the extremity. 



Test thick; the left valve, in well-preserved specimens, is marked by numerous 

 strong, simple, sharp rays, which are continuous from the umbo to the margin, with 

 rarely intercalated finer rays; crossed by regular, sharp elevated, concentric lamellae 

 which (in good specimens) are produced into sub-tubular, spiniform extensions upon 

 the rays. Lines of growth are seen between the lamellae. On the wing the rays are 

 more subdued while the concentric lamellae are strong. The ear is marked only by the 

 crowded concentric striae. On the right valve the radii are obsolete on the body and 

 well-marked on the wing, and the lamellose expansions are conspicuous. In some casts 

 they appear as undulating elevated lamellae. 



Pallial line extending parallel to the margin of the shell and terminating in a muscu- 

 lar impression on the posterior slope. A small muscular impression is also seen just in 

 front of the beak, and obscure indications of one or two cardinal teeth. 



Ligamental area narrow, striated, marked by two or three slender grooves, which 

 are slightly divergent from the hinge line." 



Remarks — The identification is based on one specimen on which the surface markings 

 are obscure, which lacks a complete outline of the anterior alation, and which the 

 umbonal part is somewhat crushed and broken, and on several fragmentary moulds from 

 a sandstone. 



Occurrence — Grand Tower limestone of Little Saline Creek; sandstone member of 

 St. Laurent limestone of Little Saline Creek. 



Genus Leiopteria Hall 



Leiopteria cf. dekayi Hall 

 Plate 36, figures 8 and 9 



1884. Leiopteria dekayi Hall, Pal. New York, vol. V, pt. 1, Lamellibranchiata I, 

 pp. 164-165, pi. 19, fig. 1; pi. 20, figs. 16-18; pi. 88, figs. 5-10. 



1909. Leiopteria dekayi Grabau and Shimer, North American Index Fossils, I, p. 425, 

 fig. 555, d. 

 Hall's description — "Shell of medium size, sub-rhomboidal in general form; body 



narrowly ovate, oblique; length about equal to the height; anterior margin nearly 



vertical for one-third the length of the shell, thence broadly rounded over the basal 



margin and abruptly recurved at the post-basal extremity. 



Left valve convex, gibbous on the umbo. Right valve smaller and less convex; 



the limitation of the wing not strongly defined. 



