152 CARBONIFEROUS LAMELLIBRANCHIATA. 



Scaldia minuta, Hind, 1899. Plate XXV, fig. 17. 



Scaldia minuta, 1899. Trans. N. Staff. Field Club, vol. xxxiv, p. 93, pi. iii, 

 figs. 1, 2. 



Specific Characters. — Shell equivalve, slightly inequilateral, very small, sub- 

 orbicularly or broadly ovate, compressed. The anterior end is deep, and has a 

 regularly rounded margin passing with a regular sweep into the inferior border, 

 which is convex. The posterior border is regularly rounded, about the same depth 

 as the anterior margin. The hinge-line is very gently arched, and forms an 

 obscure obtuse angle with the posterior border. The umbones are small, sub- 

 central. The valves are regularly convex, without a ridge, and somewhat 

 compressed along the dorsal slope. 



Interior. — Unknown. 



Exterior. — The surface of the valve is ornamented with somewhat irregular, 

 concentric grooves and ridges, well marked in the lower half of the valve, but 

 almost obsolete in the umbonal region, few in number, and large compared to the 

 size of the valve. Periostracum thick and wrinkled. 



Dimensions. — PI. XXV, fig. 17, measures — 



Antero-posteriorly . . . .3 mm. 



Dorso-ventrally . . . .2*5 mm. 



Localities. — In nodules of calcareous haematite in an indurated clay at Weston 

 Coyney, near Longton, Staffordshire. The real horizon is at present not ascertained. 



Observations. — Mr. J. Ward, F.G.S., to whom is due the merit of the discovery 

 of a marine fauna at the horizon mentioned above, has kindly placed specimens of 

 the shell in my hands for description and taken me with him to collect at the spot. 



Pterinopecten papyraceus, Discrna nitida, and a nautiloid shell occur with the 

 little Lamellibranch now described, but the latter is represented by a much larger 

 number of individuals than the other fossils. 



In the absence of details of the hinge it is impossible to say with certainty to 

 what genus the shell really belongs, but its general aspect is that of the family 

 Jlldmondidae, and its suborbicular sulcated form has induced me to place it for the 

 time being in the genus Scaldia of de Koninck. 



The periostracum is very thick, and in poor specimens often obscures the shape 

 and characters of the valve ; indeed it is impossible in many specimens to recognise 

 (lie specific characters; and, like Carbonicola Vinti, owing to crushing and the 

 consequent dislocation of the umbo, some specimens have a Discinoid look. 

 Fortunately a few specimens have been well enough preserved to indicate the 

 I iamellibranch nature of the valve without a shadow of doubt, It must be confessed 



