page 122 note 2 Sowerby's species is a fossil of the Inferior Oolite, originally described (M. C. t. 220, fig. 2) from Dundry. He gives two figures, but does not distinguish them by letter or numeral. The specimens are not in the type collection at the New Natural History Museum. Nevertheless, since a fossil similar to the right-hand figure is so common in the Inferior Oolite of Bradford Abbas and elsewhere, we cannot be in doubt as to the form of Sowerby's species. That author says that ' the granulated surface is the result of decussating furrows which vary in depth and number in different individuals.” I have examined a large series of English specimens from the Inferior Oolite, and find that Sowerby's P. granulata, though subject to great variety, has a much wider spiral, angle, is more umbilicated, and has a greater. variety of ornamentation. Nevertheless there are forms in the Inferior Oolite of Normandy classed by Deslongchamps as varieties of P. granulata (see Mem. Soc. Linn. Norm. vol. viii. pi. 16, fig. 6a), which lead up to the Cornbrash species, and also to the form now under consideration. See also a figure in Quenstedt's Der Jura, pi. 57. fig. 7, of a fossil from the Brauner Jura delta, p. 414. Still the elements of the Pleurotomaria in the Yorkshire Cornbrash, which must be regarded as very closely related to the shell now figured, are clearly not those of PL granulata, Sow., in any respect beyond the granulated character of the general sculpture. We have seen that Sowerby regarded the granulated surface of his species as the result of decussating furrows varying in depth and number; hence, when we bear in mind like wise the great differences in external appearance due to various conditions of mineralization, too much stress should not be laid upon mere granulation.
