W. E. Hudleston—The Yorkshire Oolite. 119 



Eight to nine yards farther north, in the soda-granite, another 

 band {d) exists, with the same strike — that of the schist — which 

 outcrops for two hundred feet, or as far as the rocks in the direction 

 are uncovered. This band is grey, like the last, and sparkles with 

 the same pearly mica, but it is made up largely of brown staurolite 

 in a half-granular form, showing but rarely crystalline faces, and 

 contains also disseminated magnetite and some fibrolite and chlorite; 

 a garnetiferous portion contains much black mica. Eight feet farther 

 north, but to the eastward a few yards, a very siliceous schist appears 

 for a short distance. Fifty feet north, in the soda-granite, is still 

 another band (e), which contains much chloritic magnetite; and a 

 hundred feet beyond, another thin, grey, micaceous band resembling 

 closely ¥ ; the condition of a portion of it is shown in Figure 3, on 

 page 111. Farther north, at intervals, other schistose bands exist, 

 and along the north side of Cruger's Point, facing the brick-yards at 

 the foot of Park-street, they are more largely displayed. 



(To be concluded in our next Number.) 



IV. — Contributions to the Paleontology of the Yokkshire 



Oolites.' 



Pakt VII. 



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



President of the Geologists' Association. 



(PLATE IV.) 



Genus Trochotoma, Deslongchamps,^ 1842 = Ditremaria, 



D'Orbigny, in part. 



In England the Great Oolite of Minchinhampton contains the 



greater number of species belonging to this peculiar group of 



HaUotidce. Morris and Lycett (Great Oolite Mollusca, p. 80) give 



a full and interesting diagnosis of the genus, which has only one 



representative in the Corallian beds of Yorkshire. D'Orbigny figures 



half a dozen species of Trochotoma from the Corallian of France, 



and Buvignier gives three from the Coral Bag of the Meuse. None 



are quoted by De Loriol from the Sequanien of Boulogne. 



49. — Trochotoma tornatilis, Phillips, 1829. Plate IV. 

 Figs, la, b. 

 Trochus tornatilis, Phillips, 1829, Geology of Yorkshire, vol. i. pi. iv. fig. 16. 

 Trochus discoideus, Eoemer, 1836, Ool. Geb., p. 150, pi. xi. fig. 12. 

 Trochotoma discoidea, Eoemer, 1850, Morris and Lycett, Gt. Ool. Moll. p. 84. pi. x. 



fig. 10. 

 Trochotoma discoide i. Buy., 1852, Stat. geol. de la Meuse, p. 39, pi. 25, figs. 10-11. 

 Ditremaria amata, D'Orb., 1852, Ten-. Jurass. vol. ii. p. 389, pi. 343, figs. 3-8. 



1 Concluded from the Febiniary Number, p. 69. 



2 I am indebted to Professor M orris'f or the following note ■with reference to the 

 authorship of this genus: — "Described by Deslongchainps in 1841, and first 

 published in the Mem. Soc Linn. Norm. vol. vii. 1842. Lycett sent the proposed 

 name with a specimen to Sedgwick in 1841, but without any description. The first 

 description by Lycett appears to be in the Annals and M agazine of Natural History 

 for 1848, 2nd series, vol. ii. p. 253, and more fully in the Great Oolite Mollusca, 

 1850. It would seem therefore that Deslongchamps has the priority of publication. 

 S. P. Woodward in his Manual assigns it to Lycett, although both authors suggested 

 the name Trochotoma about the same time, 1841-42." 



