W. H. H'udleston — On the Yorhhire Oolites. 245 



which, under certain circumstances, become a striato-punctate 

 structure. This is especially noticeable in that portion of the 

 penultimate shown in Fig. 5a. 



(Fig. 6). — Specimen from the Cornbrash. Leckenby Collection. 



This serves to show the apical conditions before the varices attain 

 to much importance. 



Belations and Distribution. — If we regard the subject of these 

 large Chemnitzias in anything like a philosophical and compre- 

 hensive spirit, we can hardly fail to give at least a partial assent to 

 the sweeping suggestion of MM. Hebert and Deslongchamps already 

 quoted. That Cliem. lineata-procera, the typical Bajocian form, 

 Ghem. vittata, the typical Bathonian form (in Yorkshire), and Chem. 

 Heddingtonensis, the typical Oxford-Corallian form,^ are closely 

 connected, it is impossible to deny. They occupy, in a certain sense, 

 the relative positions of a number of generations as one sees them 

 depicted in some ancestral gallery, where the family features, 

 though recognizable, are modified ; but where the costume of the 

 period, like the mineral condition of the fossil, serves to emphasize 

 and even to exaggerate such differences as may exist. 



Chem. vittata chiefly differs from the other forms in the salience 

 of its varices, and especially of the lower one, which is but faintly 

 seen in other Jurassic Chemnitzias. Dr. Lycett^ has pointed out 

 how it differs from members of the Gh. coarctata group. This we 

 can understand, as they are of different age. Yet Gh. vittata should 

 have its representative in other Bathonian beds besides the Corn- 

 brash of Yorkshire, though at present I am unable to say that the 

 pi'ecise form has been quoted from any of the noted Bathonian 

 localities, such as the Boulonnais (Rigaux and Sauvage). Langrune 

 in Normandy (Deslongchamps), or our own beds of Great Oolite 

 age, including of course the Cornbrash of the midland and southern 

 counties. 



14. — Chemnitzia Heddingtonensis, Sow. See •'' Corallian 

 Gasteropoda." 

 Imperfect forms of Chemnitzia are found in the Lower Calcareous 

 Grit, which may be referred to this " species." 



15. — EuLiMA L^viGATA, Morris and Lycett, 1850. Plate VI. 

 Figs. 7 and 8. 

 1850. Uulima Icevigiafa, M. and L., Gt. Ool. Moll. p. 114, pi. xv. fig. 4. 



Bibliography, etc. — The type is quoted from the " Great Oolite " 

 near Scarborough. That is really our third zone, viz. the Hiimphre- 

 sianus-zone of the Inferior Oolite. The figure is somewhat mis- 

 leading. Lycett, in his Supplement (p. 13, pi. 31, fig. 3), figures 

 a specimen from the Cornbrash, which he contrasts with Eulima 

 communis from the real Great Oolite of Minchinhampton. 



Description (Fig. 7). — Type refigured. — Specimen from the Scar- 

 borough Limestone (zone 3). Bean Collection, British Museum. 



Length 15 mm. 



Width 5 ,, 



Spiral angle 22°. 



^ See Corallian Gasteropoda, Geol. Mag. 1880, p. 393. ^ gp. cit. 



