392 W. H. Hudleston—The Yorkshire Oolite. 
also given by De Loriol and Pellat (Jurassique Supr. du Boulonnais, 
pl. vili. fig. 4) of a shell from the Séquanien of Houllefort, which 
the authors refer to this species. If correctly drawn, it represents a 
specimen which has suffered somewhat from wear. On the whole, 
Sowerby’s original figure is better for the purposes of specific identi- 
fication, than any other known to me. Deslongchamps quotes this 
highly characteristic Corallian species from the Inferior Oolite of 
Normandy, but it is more than probable that D’Orbigny was right in 
rejecting this identification. 
Description.— Fig. 1a. Specimen from the base of the Coralline 
Oolite at Pickering (my Collection). 
Wength (restored) <7 s\socw wosesc eres sioc es 120 millimétres. 
SW Sel Gla 21055 Wes SRA ees Seve ae Nea Oe ae ere reel by 30. ,, 
Length of body-whorl to entire shell .......... 34: 100. 
Spiral angle 
Shell elongated, conical, subturrited anteriorly, not umbilicated. 
The spire increases under a regular angle of 21°. About 10 mm. of 
the apex is wanting. The upper whorls are smooth and almost flat, 
though sharply separated by the sutures. As the shell increases, a 
varix in the upper third of the whorl becomes more and more pro- 
nounced with each turn of the spire, and this is succeeded by a slight 
hollowing out of the middle of the whorl. Thus a most unmis- 
takable character is imparted to the entire shell, as each of the 
lower whorls is angular above, depressed in the centre, and convex 
in the lower half. In this specimen the body-whorl is but slightly 
tumid. The lines of growth are unusually well preserved, the 
original shell substance being replaced by a brown-coloured spar, 
and it is even possible in places to discern a very minute punctate 
ornament arranged transversely (as shown in Fig. 1c). 
Very large individuals of this species are found in the Malton 
Oolite, often beautifully preserved in white spar, but rarely with 
ornaments so sharp as in the specimen figured. 
Fig. 1b.—Specimen from the Coralline Oolite of Ness (my Collec- 
tion). Front view of a fragment with the shell in a very different 
state of preservation to the preceding, but showing the aperture 
favourably. 
ene phi(restored) hee se cisieiarecwecee eee 117 millimétres. 
Wat cir coe eyeic a etess wie He vatshtede Slee cere ae Som iss 
Length of body-whorl to entire shell .......... 34: 100. 
Spiral angles. sys cask Maven ye bi lube ane helene 22°. 
Outer lip slightly compressed (the edge is a little ragged); anterior 
margin of aperture very oval; posterior extremity pointed; inner . 
lip of moderate thickness and encroaching but little on the 
columellar area. 
Fig. 1¢.—Specimen from the Coralline Oolite of Malton; and 
Fig. 1d.—Specimen from the Coralline Oolite of Ampleforth Beacon 
(my Collection). 
These are representatives of Chem. Heddingtonensis in its earlier 
stages, when the whorls are perfectly flat. It will be seen that the 
larger specimen is just beginning to develope the varix, and has the 
punctate ornament unsually well preserved. 
