Vol. 62.~] LIASSIC DENTALIIDiE. 579 



1-2 inches in length. It is the one figured in ' The Yorkshire Lias ' 

 (pi. ix, fig. 13), and is now at the Museum of Practical Geology, 

 Jermyn Street [7998]. It shows well the characteristic features of 

 the species, and is an angulata-bed fossil, occurring in dark shale 

 with many shell-fragments. Dentalium etalense certainly attains its 

 maximum in the angidata-be&s and rarely occurs above or below. 



Dentalium giganteum, Phillips. (PL XLY, figs. l(5a-16b & text- 

 fig. 1, p. 580.) 



T.cl. 1876. Tate, 'The Yorkshire Lias' p. 331. 



T.f. 1829. Phillips, ' The Geology of the Yorkshire Coast ' pi. xiv, fig. 8. 

 T.l. Robin Hood's Bay (Yorkshire). 

 jff. ' Middle Lias.' [Pliensbachian.] 

 ?7. [margaritati.~\ 

 Colin. York Museum. 



Dentalium giganteum, Morris, 1843, ' A Catalogue of British Fossils ' 1st ed., 

 p. 143 ; Gavey, 1853, Quart. Journ. Geol. Soc. vol. ix, p. 34 ; Oppel, 1856, 

 'Die Juraformation Englands, Frankreichs & des siidwestlichen Deutschlands' 

 p. 173 ; Wright, 1858, Quart. Journ. Geol. Soc. vol. xiv, p. 26; ? Terquem & 

 Piette, pars, 1865, 'Le Lias Inferieur de l'Est de la France' Mem. Soc 

 Geol. France, ser. 2, vol. viii, pp. 67-68 ; Tate, 1876, ' The Yorkshire Lias ' 

 pp. 331-332 & pi. ix, fig. 10 ; Beesley, 1877, Proc. Geol. Assoc, vol. v, p. 183. 



Syn. 1822. Dentalium entails, Young & Bird, 'Geological Survey of the Yorkshire 

 Coast ' p. 244 & pi. xi, fig. 13. 

 1828. Ibid. 2nd ed. p. 250 & pi. xi, fig. 20. 



1854. D. entale, Morris, 'Catalogue of Brit. Fossils ' 2nd ed. p. 246. 

 Non 1904. D. giganteum, Richardson, ' Handbook to the Geology of Cheltenham ' 

 p. 219. 



Diagnosis. — Shell distinguished by its great length, being often 

 3 inches long and a quarter of an inch in diameter at the aperture, 

 slightly curved, thick, smooth, cylindrical, but somewhat quad- 

 rangular, and slightly sulcated towards the apex. 



Remarks. — This well-known Yorkshire fossil was first figured 

 by Young & Bird, and described by them as ' belonging to the species 

 I), entalis, or one nearly the same,' but not being- Linne's species was 

 figured by Phillips as Dentalium giganteum. His figure, however, 

 is not at all satisfactory, though a good one was furnished by Tate & 

 Blake in their 'Yorkshire Lias,' and a copy of this is given on 

 PI. XLY, fig. 16 a, with the addition of a transverse section (fig. 166). 

 The transverse section is sometimes circular, sometimes quadrangular. 

 Tate {pp. cit. p. 332) remarked that 



' the species was gregarious in what is now called Cleveland ; myriads of them 

 may be seen covering the upper surfaces of some of the sandstones situated near 

 to the base of the Zone of Ammonites margaritatut at Hawsker, Staithes, Rock- 

 cliff, Hummersea, Huntcliff, and Coathain Scars, on the coast, and inland at 

 Hutton, near Guisboro', and in Danbydale. It is found on the same horizon 

 in Lorraine and in North Germany.' 



No description of the species was furnished by Phillips. The 

 diagnosis here given was taken from Tate's in ' The Yorkshire 

 Lias,' some slight alterations being made. 



In the Geological Society's Museum at Burlington House there is 

 a piece of rock containing a number of worn fragments embedded 

 in a brown and grey earthy limestone (of margaritati hemera 



