LINGULA. 200 



Bishopbriggs and Robroyston, north of Glasgow, in Renfrewshire at Orchard Quarry, 

 Thornliebank. In Ayrshire at West Broadstonc, Beith. In Stirlingshire at Craigenglcn 

 and Corrieburn. In Fifeshire, at Craig Hartle, &c. It has also been found along the 

 Berwickshire coast, and at Marshall Meadows, three miles north of Berwick. In 

 Ireland it has been found in Tyrone, Desertcreat, also at Cloghcr (Pollock). On the 

 Continent it has been described by Prof, de Koninck, from Vise, in Belgium. 



Lingula Chedneri, Geinitz. PI. XLVIII, figs. 38 — 40. 



Lingula. Credneri, Geinitz. Versteinenuigen der Zechteingebirges, pi. iv, figs. 23 — 

 29, April, 1848. 

 — — M'Coy. British Palaeozoic Fossils, p. 474, 1855. 



— Kirkby. Proceedings of the Geol. Soc, vol. xvi, p. 412, 1860. 



Spec. Char. Shell small, oval, occasionally oblong, with the posterior end acuminated 

 valves gently convex ; marked with concentric lines of growth. Interior unknown. Length 

 3, width 1\ lines. 



Obs. Is this shell specifically distinct from L. myliloides ? Might it not be a small 

 variety of the last-named shell ? Indeed, I would hardly venture to positively assert that it 

 is specifically distinct. Until March, 1860, L. Credneri was known only from the "marl 

 slate" and the lower beds of the compact limestone of the Permian system, but Mr. 

 Kirkby informs us that the shell occurred to him as a Carboniferous species at Ryhope 

 Winning, near Sunderland, in the summer of 1858 ; that he observed it first in a thin bed 

 of dark shale, at a depth of 951 feet from the surface, or 592 feet from the base of the 

 overlying Permian strata, though in this bed it was exceedingly rare ; but that he found it 

 more plentiful in a thick stratum of gray shale just above the bed already mentioned. 

 That from the first (to use his own expression) he was struck with the resemblance of 

 these Lingulce to the Permian species, L. Credneri, and that his opinion was only strengthened 

 by the acquisition of a full suit of specimens, and which he submitted to Mr. Hancock's 

 and my own examinations. 



There is no essential difference (he adds) between the Permian and Carboniferous 

 specimens. The form of both is* nearly oval ; the Carboniferous specimens have the median 

 elevation more prominent than those of the marl state, but that in this respect they only 

 approach more closely r the Permian example from the Kupsfer Schiefer, the German 

 equivalent of the marl slate, and that in no respect do the Permian examples differ from 

 the Carboniferous sp cimens more widely than do individuals of the same series from 

 each other. 



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