The Occurrence of Reticuloceras reticulatum in the Culm of North Devon

Extract

Reticuloceras Reticulatum is the typical goniatite in the topmost beds of the Sabden Shales of Lancashire. This form is known from the Exeter district (Collins and Crick, Q.J.G.S., vol. lxvii, 1911, p. 393), but apparently the only recorded occurrence of this form in North Devon is by Wheelton Hind, who, in the report of a lecture on the correlation of the rocks in North Devon with other areas, is stated to have said, “Glyphioceras reticulatum has been obtained by Mr. Inkermann Rogers” (Proc. Geol. Ass., vol. xxi, part viii, p. 463). In the summer of 1928, Mr. Rogers was good enough to take the writer over the ground at Ilsey Beach, Lower Yelland, where he had obtained the specimen in question. The beds on this beach contain Goniatites spiralis and other goniatites, but not R. reticulatum. Inquiries at the British Museum (Natural History) elicited the information that no R. reticulatum from Devon was in the Hind Collection. As the specimen cannot be traced, confirmation is impossible. Its identity with R. reticulatum, however, is manifestly erroneous, owing to its association with G. spiralis, and with the lamellibranch, Posidonomya becheri, forms which do not survive to the top of the Bowland Shales of Lancashire.