1872.] BLAKE YORKSHIRE INFRALIAS. 147
4. CYTHERE Terquemiana, sp. nov.
Carapace narrow-oblong, incurved on the back by the projection of the anterior hinge, and pinched in between that hinge and the muscle-spot ; rounded at the ends, with broad delicate margins, that of the front divided into about eight neat fossets. Surface sculptured with a coarse, irregularly hexagonal network, about eight meshes to the transverse width of the valve.
Length 1/50 inch. Three specimens.
This form reminds us of the Tertiary Cythere canaliculata (Reuss) and its varieties ; but its compression is stronger and more central, and its reticulation has far less tendency to run into ridges by the hypertrophy of the meshes.
This species is dedicated to M. O. Terquem, the veteran explorer of the Lias of Metz and its neighbourhood.
Discussion.
Prof. Duncan remarked that English geologists had been backward in receiving the term Infralias, which he had suggested with respect to the Sutton Down beds some years ago, and the propriety of which was shown by the term having been applied to the same beds by French geologists at a still earlier period. As to the White Lias, he regarded it as a mere local deposit, not to be found out of England. He traced the existence of the Infralias from Luxembourg through France into South Wales, where Corals were abundant. In Yorkshire, though one fine Coral had been found, the Ammonites seemed to point to a difference in condition.
Mr. Hughes remarked that the lithological character of the beds, as described by the author, did not agree with that of the Infralias in the S.W. of England or the N. of Italy, and that the palaeontological evidence which had been laid before the Society did not confirm the view that they were Infralias. Also, by reference to the author's section, Mr. Hughes pointed out that below what he described as Infralias he drew other beds which were not Trias, the author having explained that some beds which had been called Trias were only stained beds of Liassic age.
The Rev. J. F. Blake, in reply, acknowledged the difference between the Yorkshire section and those of the neighbourhood of Bath, but insisted on the similarity of the fossils.
February 7, 1872.
W. G. Thorpe, Esq., of Gloucester House, Larkhall Rise, S.W., and Barton's House, Ipplepen, Newton Abbot, and James Plaat, Esq., of 40 West Terrace, West Street, Leicester, were elected Fellows of the Society.
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