TEREBRATULA. 19 



8. Terebratula bisinuata? Lamarck. Plate I, fig. 17. 



Terebratula bisinuata, Lamarck. 1819. An. Sans Vert., vol. vi, p. 252, No. 32; 



aud Davidson, Notes on an Examination of Lamarck's 

 Species of Foss. Ter., Annals and Mag. of Nat. Hist., 2d 

 ser., vol. v, No. 32, pi. xiii, fig. 32. 



— — Beshayes. Coq. Foss. des Env. de Paris, torn, i, p. 65. 



— fragilis, Kcenig. 1825. Icones Sect., No. 45. 



— gigantea, V. Buch. 1838. Mem. de la Soc. Geol. de France, vol. iii, 



p. 222, pi. xx, fig. 3. (non T. gigantea, Schl.) 



— grandis, Bronn. 1848. Index Pal., vol. ii, p. 1237. (non T. grandis, 



Blum.) 



— bisinuata, B'Orb. Prodrome, 1849, vol. ii, p. 395. 



— — D'Jrchiac. Hist, des Prog, de la Geol., vol. iii, p. 276. 



Diagnosis. Shell ovate, longer than wide ; large valve convex, longitudinally keeled, 

 a slight lateral depression causing the valve to project more in that part ; beak nearly 

 straight, and obliquely truncated by a large foramen separated from the umbo by two 

 small deltideal plates ; surface smooth, marked only by a few concentric lines of growth : 

 length twenty-two, breadth nineteen lines. 



05s. The discovery of this Terebratula in our lower tertiary deposits is due to 

 Mr. Prestwich, who unfortunately found only the larger valve in the Bracklesham sands, 

 now considered to be the equivalent of the lower beds of the Calcaire Grossier of France, 

 where this same species has been found at Grignon, Parnes, Chaumont, Courtagnon, 

 Mouchi, &c. We cannot, however, help stating that our determination of this shell is not 

 as satisfactory as we might have wished from the imperfect state of the specimen ; this 

 seems a rather thicker shell than the French T. bisinuata, the foramen is larger, and the 

 deltideum more concave, and it much resembles a shell found in more recent tertiary 

 formations in Sicily. It is to be hoped that future researches in the Bracklesham sands 

 may bring to light a more complete specimen. 1 



Plate I, fig. n ab . Specimen from the collection of Mr. Morris. 



1 Since writing the above, and after my plate was printed, Mr. Cunnington, of Devizes, was so fortunate 

 as to discover another and more complete specimen than the one described above. Mr. Cunnington's 

 specimen is smaller, much compressed by pressure, but with both valves ; it is circular, rather longer than 

 wide, very thin, not much convex, and presenting scarcely any trace of the bisinuation, — a characteristic of 

 the Lamarckian type, but which is not always distinctly visible on the Grignon specimens ; and I think we 

 may consider our determination as probable, if not certain. Mr. Cunnington's specimen is from the 

 London Clay of Barton or Hordwell Cliffs, on the Hampshire coast. It measures in length 13^; in 

 width 12 lines. 



