244 W. H. EiuUeston — On the Yorkshire Oolites. 



There is a form of CJiemnitzia which occurs in the Dogger, and 

 perhajDS in the Scarborough Limestone, having a larger spiral angle, 

 and being altogether of a stouter build than Ch. lineata. This 

 perhaps was noticed in the earlier editions of Phillips as Melania 

 Heddingtonensis, Sow., but in the last edition (1875) that species is 

 not quoted from the Lower Oolites — Ch. Scarburgensis apparently 

 taking its place. 



Now of course Ch. Scarburgensis may be made to cover anything, 

 being simply the flattened cast of a lai'ge Chemnitzia, belonging in 

 all probability to the lineata-procera group. 



Nothing mope can be done at present than simply to point out the 

 fact of the occurrence of this stouter form, which, as far as I can 

 judge, is less turrited than Normandy specimens of Chem. coarctata. 

 No specimen sufficiently good for determination from the Yorkshire 

 beds has ever come into my hands. 



13.— Chemnitzia Vittata, Phillips, 1829. PI. VI. Figs. 5a, 5b, and 6. 



1829 & 1835. Melania vittata, Phil., G. T. p. 116 (ed. 1835), pi. vii. fig. 15. 

 1853. Chemnitzia vittata, Phil., Lycett, Suppl. p. 14, pi. 31, fig. 10. 

 1875. Chemnitzia vittata, Phil., G. T. 3rd ed. p. 257. 



Bibliography, etc. — This species was adequately described and 

 figured for the first time by Lycett, who alludes to the fact that 

 D'Orbigny (Prod. vol. i. p. 295) supposed Nerincea suprajiirensis, 

 D'Archiac, might be the same. Oppel (Jura Formation, p. 479) in 

 bis synonymy accepts D'Orbigny's supposition. Lycett does not 

 favour the view. 



Description (Figs. 5a, 5b). — Specimen from the Cornbrash. (zone 4), 

 Scarborough. Leckenby Collection. 



Length (complete) 112 mm. 



Width 32 „ 



Length of body- whorl to entire shell 30-5 : 100. 



Spiral angle 22'"'. 



Shell conical, elongate, sub-turrited. The complete spire is com- 

 posed of about ten or twelve whorls, which increase under a regular 

 angle ; and are flat and without protuberance in the early stage. 

 The apical portion of the spire is, consequently, a smooth elongate 

 cone, unbroken save by the suture, which is clean cut, rather 

 narrow, and moderately oblique. By degrees a belt, which rapidly 

 assumes the character of a varix, is formed towards the posterior 

 margin of the widening whorl. This becomes a prominent feature, 

 since it falls away very steeply towards the slightly excavated 

 median area of the whorl, which swells towards a second but less 

 pronounced varix on the anterior margin. Edges of the anterior 

 whorls bevilled off towards the strongly marked suture. In the body- 

 whorl the space between the two varices is still more hollowed out. 



The aperture is oval and tolerably wide, with fair evidence of 

 thickening posteriorly where the callus is very prominent. Inner 

 lip almost detached anteriorly. 



Being in the usual wax-like condition of fossils from the Scar- 

 borough " Cornbrash," the specimen is favourable for showing the 

 wavy lines of growth, and the peculiar granulated spiral lines, 



