106 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 
posterior inferior angle, gradually diminishing in intensity as it passes in this 
direction ; anterior to the oblique timidity the shell is flattened. Posterior to and 
above the swelling the shell is compressed and flattened into the hinge-line, the 
flattened portion often being traversed by obscure radiating lines, especially well 
marked in the young state. 
Interior.—Not known at present. 
Hevterior.—The surface is covered with lines and striz of growth, well marked 
and distinct and crowded anteriorly, becoming almost obsolete posteriorly, so that 
the posterior portion of the shell is almost smooth. The striz run parallel to the 
inferior and posterior margins, and terminate above in the hinge-line somewhat 
obliquely. The periostracum is wrinkled. 
Dimensions : 
Antero-posteriorly. Dorso-ventrally. 
Fig. 13, Pl. XV, measures . 40 mm. 16 mm. 
Bigs sae ay 3 . 30mm. 10 mm. 
Localities.—North Staffordshire: the shale over the Bowling Alley Coal’ at 
Adderley Green, Bucknali, and Whitfield. Fulledge, Burnley. High up in the 
Gannister series at Burrs, half a mile north of Bury, Lancs. Roof of Shale Coal, 
Wakefield. 
Observations.—This species was founded upon a comparatively poor specimen 
‘In the cabinet of Mr. John Ward, F.G.S., of Longton, by Mr. Salter, who, however, 
published no description ; but this omission was made good by Mr. R. Etheridge, 
F.R.S., in Mr. Ward’s book on the ‘ Geology of the North Staffordshire Coal-field ’ 
(op. supra cit.). This specimen I am able to figure on Pl. XV, fig. 14, by the 
kindness of Mr. John Ward. As i pointed out in my redescription of this fossil 
(op. supra cit.), Mr. Etheridge described the specimen with the preconceived idea 
that the shell belonged to the Anatinide, and that he mistook an imperfection for 
a central umbo, and somewhat unwisely surmised the shell to possess character- 
istics belonging to the genus Anatinids, which could not be seen in a single 
imperfect valve. The specimen is altogether too imperfect to serve as a specific 
type, but I believe that enough has been left of it to show that the shell belongs 
to a distinct species, of which I have been able to procure good examples. The 
typical posterior end of Mr. Ward’s specimen is well preserved, and there can be 
little or no doubt that it is a similar shell to Pl. XV, fig. 13, from the Kay 
Shuttleworth Collection of the Manchester Museum, Owens College, which 
probably has attained a similar stage of growth. The other specimens from the 
same Collection, Pl. XV, figs. 16, 17, and 19, and the beautifully preserved 
1 Mr. Ward gives the Holly Lane seam, but I think it is more probably the Bowling Alley, 
the next seam above which is overlain by a shell-bed. The two seams are always worked together, 
and the rubbish would be on the same tip. 
