120 W. S. EucUeston—The Yorkshire Oolite. 



Trochotoma amata (D'Orb.), 18—, Deslongchamps, Notes paltBont., No. vi. p. 46, 



pi. 3, figs. 3-6. 

 TrocJwtoma tornata, Phillips, 1875, G. T., 3rd edition, p. 359. 

 non Fleurotomaria tornata (Phillips), D'Orb., op. cit. p. 56'!, pi. 422, figs. 6-8. 



BibliograpJiy, etc. — It is certainly stretching the rule of priority to 

 the utmost when we adopt Phillips's name for this very widespread 

 and somewhat persistent species. As there is no other species of 

 Trochotoma in our Yorkshire beds of this age, it is pretty clear that 

 Phillips's most inadequate "figure was intended for the fossil now 

 under consideration. If, however, this figure, unaccompanied as it 

 is by any description, be rejected as insufficient to establish Phillips's 

 claim, we must fall back upon Eoemer'sname of Trochotoma discoidea, 

 which is in every way preferable. 



D'Orbigny (Prod, de Pal. Strat. vol. i. p. 354) quotes Trochus 

 discoideus, Eoemer, as an Oxfordian fossil, and subsequently (op. cit. 

 vol. ii. p. 9) quotes Dttremaria amata, D'Orbigny, from the Corallian. 

 In the Terrains Jurassiques he makes no mention of Eoemer's species, 

 but regards the Trochotoma discoidea, Buvignier, as a synonym of his 

 own D. amata. Brauns (Obere Jura, p. 231) regards Buvignier's 

 species as identical with Roemer's. Buvignier's figure and descrip- 

 tion answer excellently to our Yorkshire specimens, which we must 

 therefore identify with the original Trochus discoideus of the Coral 

 Eag of Hildesheim. 



Description. — Fig. 1?). Specimen from the Coral Eag of North 

 Grimston (Strickland Collection). 



Height 12 millimetres. 



Basal diameter 26 ,, 



Spiral angle, about 130°. 



Shell very depressed, more than twice as wide as high, largely 

 excavated. Spire composed of about four whorls, which are wide 

 apart, subdepressed in the early stages, and very much so in the 

 body-whorl, which is large in proportion to the rest of the spire. 

 The ornaments consist of regular raised lines parallel to the suture 

 {i.e. transverse), and these lines are cut across from left to right by 

 a system of fine striations, producing a delicate pattern. The whorls 

 are bicarinated (a feature not observable in the earlier stage) : the 

 posterior keel, which forms the salient angle, contains the fissure. 

 This is elongate, and terminates three millimetres from the present 

 margin of the outer lip, which has been slightly reduced by fracture. 

 The space between the keels is rather excavated, and the anterior keel 

 is rounded ofi". The same ornamentation is continued in the base of 

 the shell, but the state of preservation does not admit of an accurate 

 description of the aperture. 



Fig. la. — Smaller specimen from the Coital Eag of Brompton 

 (Strickland Collection). This shell has the general character and 

 ornamentation, of the one previously described, but is less depressed. 

 Moreover, the body-whorl developes wide undulations across its 

 surface, which yield an additional ornament. The imbricated band 

 of the sinus is very well seen in this specimen, situated, as in the 

 other case, on the posterior keel. The termination, where the loop 



