THE 



GEOLOGICAL MAGAZINE- 



NEW SERIES. DECADE III. VOL. I. 



So. v.— MAY, 1884. 



(D:EiXG-xi<rjL.Xj -A-is-tioXjIes. 



I. — Contributions to the Paleontology of the Yorkshire 



Oolites. 



By Wilfrid H. Hudleston, M.A., F.G.S. 



(Continued from Decade III. Vol. I. p. 154.) 



(PLATE VI. Figs. 11, lla; PLATE VII.) 



40.— Alaria trifida/ Phillips, 1829. Plate VI. Figs. 11, lla; 

 Plate VII. Figs. 1, la, 2, 3, 3a. 



1829 and 1835. Rostellaria trifida, Bean MS. Phillips, G. T. p. 109, pi. v. fig. 14. 



1842. Rostellaria trifida, Phil. Deslongchamps, Mem. Soc. Linn. Norm. vii. 



p. 171, pi. 9, figs. 27, 28, 29, non figs. 30, 31. 



1849. Pierocera trifida, D'Orb. Prod. i. p. 357. 



1850. Alaria trifida, Phil. Morris and Lycett, Great Ool. Moll. p. 21, pi. 3, 



figs. 11, etc. 

 1854, Alaria trifida, Phil. Morr. Cat. p. 235. 



— Alaria trifida, Phil. Piette, Cont. de la Pal. rran9. Fe serie, p. 149, pi. 37, 



figs. 1 — 5. 

 Compare also 



1836. Fusus curvicauda, Rcem. Ool. Geh. p. 140, pi. 11, fig. 6. 



1837. Chenopus Philippi, Dunker and Koch, Beitr. p. 34, pi. 2, fig. 13. 

 1844. Rostellaria hicarinata, Miinst. Goldfuss, iii. p. 15, pi. 170, fig. 1. 

 18 — . Alaria eochleata, Quens. Piette, op. cit. p. 110, pi. 22, figs. 1 — 6. 



Bibliography, etc. — This widely-spread, and, on the whole, well- 

 marked species, has been in so many cases, as it appears to me, 

 confounded with Alaria bispinosa, that it would be a task of no 

 small difficulty to trace out the mistakes that have arisen in conse- 

 quence. The imperfect figures of Phillips have, no doubt, been the 

 principal cause of thus confounding the two species. Deslongchamps 

 queried the identification, but yet was inclined to adopt it. Morris 

 and Lycett seem to have had no doubt on the subject. " Having 

 had the advantage of examining a large number of specimens, com- 

 prising every variety both in form and stage of growth, we feel no 

 hesitation in uniting the two species here indicated." It is extremely 

 probable that the Great Oolite specimens of Alaria trifida present 

 varietal differences from the Oxfordian types, and they may also in 

 some cases have assumed forms having only one lateral digitation ; 



1 Owing to an error on p. 146 of the April Number, Alaria trifida is represented 

 as a variety of Alaria bispinosa. According to my views the species are very dis- 

 tinct, although they constitute a group having certain features in common. 



DECADE III. — VOL. I. — MO. V. 13 



