Vol. 55.] CARB0NIFEK0T7S LAMELLIBRINCHIATA. 367 



II. Carbonicola Vinti (Kirkby). (PI. XXV, figs. 5-13.) 



(?) Aneylus Vinti, Kirkby, Trans. Tyneside Nat. Field Club, vol. vi (1864) p. 220 . 



Specific Characters. — Shell very small, inequilateral, ovate, 

 compressed. The anterior end is broad, and its border is regularly 

 rounded. The inferior border is regularly but gently convex. The 

 posterior border is narrowed by the approximation of the upper 

 and lower margins, obliquely truncate from above downward 

 and backward, making a well-marked obtuse angle with the 

 hinge-line above and an acute angle with the inferior margin below. 

 The hinge-line is arched, extended, and depressed posteriorly. The 

 umbones are small, tumid, slightly elevated, and situated in the 

 anterior fourth of the shell. 



The valves are regularly and gently convex for the anterior two- 

 thirds, but gradually compressed in the posterior third. 



Interior. — The muscle-scars appear to be normal. The hinge 

 has not yet been isolated. 



Exterior. — The surface is smooth and glistening, covered with 

 fine concentric lines and folds. Periostracum much wrinkled. 

 Shell thin. 



Dimensions. — Antero- posteriorly, 5 mm.; dorso-ventrally, 

 3 mm. 



Localities. — In a calcareous bed some yards above the Bassey 

 Mine Ironstone, in an old marl-hole near Chatterley Station ; in cal- 

 careous bands about 10 yards above the Bassey Mine Ironstone, the 

 Hamil, Burslem, Upper Coal Measures, North Staffordshire ; in a bed 

 of ironstone in the northern bank of the Wear, opposite Claxheugh, 

 Upper Coal Measures, Durham. 



Observations. — A very full account of the history of the 

 discovery of this fossil is given by Mr. J. W. Kirkby (op. supra cit.), 

 who was disposed to admit the lamellibranchiate character of this 

 little fossil, which was considered by some high authorities to be 

 a gasteropod (Aneylus), by others to be a brachiopod allied to 

 Discina, and was thought by yet others to be a crustacean. 



I have referred my specimens to Mr. Kirkby, Prof. T. Rupert Jones, 

 and Dr. G. J. Hinde, with the following result : — The latter two 

 gentlemen consider that the shell is a lamellibranch, and Mr. Kirkby 

 writes that it is identical with his Aneylus Vinti. The specimens 

 that I have of 'Aneylus Vinti ^ from the Durham beds, kindly 

 sent by Mr. Kirkby, seem to me to be simply the closely compressed 

 remains of the periostracum of a large number of shells, a circum- 

 stance which probably accounts for the difficulty in accurately 

 determining the fossil. 



Fortunately the North Staffordshire specimens are much better 

 preserved, and, though generally somewhat crushed, show the 

 general outline and character of the shell, and are therefore more 

 easily referred to their real family and genus. After discussing 

 the question of the true affinity of this shell at length, Mr. Kirkby 

 finishes by saying : — ' Por the present, therefore, it will be as well, 

 perhaps, to retain as a provisional name Prof. Phillips's term of 



