ON SOME CARBONIFEROUS AMMONOIDS NEW TO ENGLISH ROCKS

Abstract

(Read November 26th, 1919). The quarry at Kniveton, Derbyshire, north of Standlow farm, has yielded a fauna characteristic of Vaughan’s Caninia horizon and certain goniatites new to England occur there. Two of them have been described from a similar horizon in Ireland. It is important to publish these facts and to figure the English specimens in order to establish a Goniatite zone in Upper C beds, which is lower than any previously known in the Carboniferous series. Three species of Ammonoids, which are unknown at other levels, characterise the horizon— Pericyclus fasciculatus M’coy, Glyphioceras inconstans de Konmck, G. corpulentum Foord. GLYPHIOCERAS INCONSTANS, de Koninck, 1880. Glyphioceras inconstans de Koninck, 1880; Ann. Mus. Roy. d’Hist. Nat. de Belgique, Faune de Calcaire Carb. de la Belgique , Tom. V., 2me Pt., p. 120, Pl. XVIII, figs. 4, 5, 6, 7, 8, 9. Specific Characters.—Shell discoidal, compressed, involute, attaining a diameter of 70 mm. in well-grown examples. Greatest thickness at the umbilical edge. Inclusion not complete. Whorl sub-elliptical. Body chamber occupying almost the whole of the last whorl. Whorls several. Periphery regularly arched in the young, becoming flattened in the larger specimens. Umbilicus small and deep, its margin rounded and simple. Camerae are deep—about 8 to the whorl. Shell apparently thin, ornamented by almost obsolete transverse lines of growth, arched sinuously on the periphery, so that they are slightly concave forward and form a very shallow sinus there. The suture line : the peripheral lobe is deep and broad, with parallel borders, …