W. n. Hudleston — On the Yorkshire Oolites. 247 



Besides tlie very great differences in appearance superinduced by 

 the cliaracter of the matrix, there really does seem to have been 

 considerable regional variation in a set of forms, which Deslong- 

 champs, for the I. 0. of Normandy, focussed under two headings, 

 viz, Melania undulata, and Melania scalariformis. Some of these 

 varieties may be noticed in the I, 0. of Bradford Abbas, where very 

 fine spathic fossils are to be had. The Dundry variety is referred by 

 Mr. Tawney to M. undulata} The group is perhaps more character- 

 istic of the Lias ^ than of the Oolites, and it does not appear to ascend 

 in its more typical form, above the Lower Oolites,^ at least in York- 

 shire. But in the 1st and 2nd zones of the Inferior Oolite on the 

 coast there are certain forms which exhibit such constant variety as 

 to render them worthy of some notice. 



16. — " Chemnitzia " VETUSTA, Phillips, 1829. Plate VL Figs. 9, 



10, 11. 



1829 and 1835. Terebra vetusta, PhU., G. Y. p. 123, pi. ix. fig. 27. 



1840. Ibid. Ibid. WilKamson, Trans. Geol. Soc, 2nd series, 



vol. V. p. 241. 

 1842. Melania scalariformis (pars) (? Deshayes), Deslongclianips, Mem. Soc. Lion. 



Norm. vol. vii. p. 218, pi. xi. figs. 63-66. 

 1844. Gerithium fiexuosum, Miinst., Goldfuss, t. 173, fig. 15. 

 1850. Chemnitzia vetusta, D'Orb. (Phil.), Prod. vol. i. p. 263. 

 1869. CeritJiium vetiistum, "Williamson, Brauns, Mitl. Jura, p. 172. 

 1875. Chemnitzia vetusta, Phil., G. T. 3rd edition, p, 257, pi. ix. fig. 27. 



Bibliography. — Brauns further unites under this " species " C. ar- 

 matum, Goldf., C. echinatum, Von Buch, C. muricatum, Quens. pars, 

 ? Mel. undidata, Desl., C. gramdato-costatum, Miinst., and muricato- 

 costatum, Mtinst., C. gramdato-costatum, Quens. (Jura, pi. 65, fig. 

 22, and Foss. of Montreuil-Bellay, pi. 7, fig. 1), and C. tortile, 

 Heb. & Desl. 



Evidently this is a stable that requires a good deal of cleansing, 

 but to refer all these to the Cloughton shell is, it seems to me, to act 

 ■under a misapprehension, more especially as Brauns considers that 

 the figures of Phillips, and of Morris and Lycett, do not represent 

 the same species. 



Certainly these figures present a different appearance, but at any 

 rate we can have no difficulty as to the identification of Phillips's 

 type, which the author says expressly comes from the " Oolite " of 

 Cloughton Wyke. The exact bed is well known to all those who 

 are acquainted with the palseontological stratigraphy of the district. 

 It is a subcalcareous and ferruginous grit in the upper part of the 

 Millepore Bed, In Phillips's figure the costge are rather too close 

 together, and too numerous. They are not decussated. 



1 Dundry Gasteropoda, p. 11. 



2 Strong longitudinal ribs, straight or slightly curved, and but little decussated ; 

 an aperture, ■which, ■when one can see it, has a tendency to a slight channel in the front, 

 but is otherwise Chemnitzoid ; these features characterize the group of which several 

 species are enumerated, and some ne'w ones described by Tate and Blake in their 

 Memoir on the Yorkshire Lias. 



3 Some fossils lately discovered by the Survey in beds of presumed Lower 

 Oxfordian age in Lincolnshire (on the horizon of the Scarborough Kelloway 

 Eock perhaps) appear to represent the group. 



