Pernopecten carboniferus (Hind, 1903)
HIND, W. 1903. A Monograph of the British Carboniferous Lamellibranchiata. Volume 2, Part 2: 35-124, pls. 7-21 (Issue 268, part of Volume 57). The Paleontographical Society. London. [p. 120, pl. 19, figs. 3-6]
1903 Syncyclonema carboniferum Hind, 1903 [partim]
W. Hinds, 1903, plate 19.
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«Specific Characters.— Shell small, obovate, expanded, very slightly convex; more so near the umbo. Margins of valve small, the anterior the larger. Hingeline narrow. Ears triangular and raised so that their upper margins meet at the umbo at an obtuse angle, the anterior a little larger and deeper than the left. Umbones small, pointed, swollen, not elevated. Shell very thin.
Interior.— As in S. Sowerbyi. Exterior.—The surface is ornamented with very fine, close, concentric ribs, only visible under the microscope. Ears smooth. Dimensions.— PI. XIX, fig. 5, a right valve, measures -- Antero-posteriorly . . . .11 mm. Dorso-ventrally . . . . 15 mm. Locality.— England: the Marine Band above the Gin Mine Coal, Nettlebank Sinking, Smallthorne, North Staffordshire Coalfield. Observations.-—This little shell occurs plentifully in a bed of grey shale with calcareous bullions at the horizon and locality mentioned above. The Gin Mine Coal is high up in the Coal Measures, and occurs about 430 yards below the Bassy Mine Ironstone, which is taken as the base of the Upper Coal Measures. This bed was recognised by Mr. Ward so long ago as 1865, while a sinking was going on at the Speedwell Colliery, Longton, and it was not until March, 1903, when Mr. Stobbs, mining lecturer under the Staffordshire County Council, noticed marine shells in the spoil-heap from a sinking at Nettlebank, that this marine bed was noticed again. The bed is of great importance, evidently, as a guide to the coal immediately below it, and the value of fossil evidence in mining is demonstrated. The following list of the fossils found with S. carboniferum will be of interest:
Many of these species are dwarfed.
S. carboniferum is much narrower than S. Sowerbyi, and I think quite a distinct species, and not merely dwarfed. I have been able to see the interior, which in every detail is similar to that of S. Sowerbyi, but the valve is markedly ornamented with fine, close, concentric lines.» WHEELTON HIND, 1903
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«REMARQUES. — La description donnée par HIND est incomplète et partiellement erronée: il confond valve gauche et valve droite et admet la même forme des ailes aux deux valves; de plus les spécimens figurés manquent d’homogénéité.
En 1936, ne disposant que d’un matériel réduit et n’ayant pas eu l’occasion de distinguer la forme différente des ailes d’une valve à l’autre chez les Pernopecten et Syncyclonema, j’admettais avec Hind la présence d’ailes pointues aux deux valves de ces genres. Aussi avais-je fait un Peudamusium nouveau, Ps. sinuosum, d’une série de valves droites à bord cardinal rectiligne, qui, en réalité, se rapportent au genre Pernopecten. La confusion était encore facilitée par le fait que les bordures de la valve droite sont beaucoup moins nettes, plus courtes et moins relevées que celles de la valve gauche, par le fait aussi que le sillon qui sépare chaque bordure d’avec le corps de la valve peut être pris pour une portion de ces larges ondulations concentriques irrégulières dont se couvre souvent par pression mécanique la valve droite des Pernopecten.» DEMANET, F. 1943. Les horizons marins du Westphalien de la Belgique et leurs faunes. Mémoires du Musée Royal D'Historie Naturelle de Belgique, 101: 1-166, pls. 1-9. [p. 102]
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Pernopecten carboniferus (Hind); F. Demanet, 1843, Les horizons marins du Westphalien de la Belgique et leurs faunes, plate 3, figures 40-43.
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