Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/441

428 138. Trichotropis borealis, Sowerby.

, Fusus carinatus, jun. Laskey.

Fusus umbilicatus, Smith and Brown.

Trichotropis acuminatus, Jeffreys.

Trichotropis costellatus, Couthouy.

, fossil. Ireland. Bridlington. [Canada.]

, living. Seas of Scotland, Scandinavia, Arctic Seas, Greenland, coasts of America from Massachusets northwards.

Note. A coralline crag fossil.

139. Cancellaria costellifer (Murex sp.), Sowerby (M. C).

, Cancellaria buccinoides, Couthouy. Cancellaria Couthouyi, Jay.

, fossil. Bridlington.

, living. Inhabits the E. coast of America, from Masaachusets to the Arctic Seas.

Note. This species appeared in our area during the Coralline Crag epoch, and continued during the formation of the red crag. It is now restricted to the other side of the Atlantic. It is essentially a Boreal form, though the genus is sub-tropical.

140. Mitra species: an Mitra cornea, Lamarck?

, fossil. A single specimen of a Mitra has occurred in the glacial beds of Wexford. It is too much broken to determine the species, but having the columella entire, with the folds perfectly preserved, there can be no question respecting the genus. Its proportions, and the number, &c., of the folds on the lip approach so nearly to those of Mitra cornea that I have little doubt better specimens will prove the fossil to have been identical with that species. I have compared it with the Mitra groenlandica (specimens of which are in the British Museum) of Möller, a species which we may expect possibly to be preserved in the drift. The Greenland shell is about the same size as our fossil, but in other respects is very different. The existence of a Mitra in Greenland is an apparent anomaly in the distribution of the species of that genus, which would seriously militate against the idea entertained by many naturalists (and to which I am inclined to subscribe) of the existence of generic centres. The shell before us does away with the anomaly, for we now find in the very beds which were deposited in a sea, the fauna of which was most nearly related to that of Greenland now, a Mitra linking, as it were, the true seat of the genus in the southern and tropical regions, with its outpost in the far north.

, living. Mitra cornea is a characteristic species of the Mediterranean and Lusitanian regions of the European Seas. It occurs fossil in the newer pliocene beds of Sicily.

141. Tornatella pyramidata, (Auricula sp.), Sowerby (M. C.).

, fossil. A well-marked, large, and entire specimen of this fine species has been found in the Wexford beds.

142. Cypræa Europæa, Linnæus.

, fossil. Irish drift.

, living. Throughout the European Seas.