W. H. Hudleston—The Yorkshire Oolite. 533 
in such a case as that of Alaria bispinosa—a common form, first 
noticed, by Phillips in the Lower Calcareous Grit of Yorkshire, but 
which may be found with more or less modification in other forma- 
tions of the Jurassic period. 
Description (Figs. 6a, b).—Specimen in a hard blue gritty lime- 
stone, said to be from the “Coral Rag” of Pickering, but more 
probably from one of the blue beds of the Lower or Middle Cal- 
careous Grit of that locality (Jermyn St. Museum). 
Length, excluding canal ....6...ccsececeeees 18 millimétres. 
Width of last whorl without wing .......... 9 ri 
PAM ENPIO datiegd stead ensacedeaaeuae eden 32°. 
Shell moderately elongated, strongly turrited. Spire composed of 
about ten whorls (apex broken off). The whorls posterior to the 
penultimate increase under a pretty regular angle, averaging 32°, and 
present a well-marked keel towards the lower third. The penulti- 
mate increases rather suddenly and with a proportionate develop- 
ment of keel. The body-whor!l still further increases and developes 
avery strong keel or varix, to which a second or anterior keel is 
subordinate. These probably support a two-fingered wing, which 
itself, together with the aperture, is concealed in matrix. 
The ornaments on the whorls consist of very fine transverse 
lines (Fig. 6b), in some cases slightly granulated. This kind of 
ornament, only noticeable in a well-preserved specimen, pervades 
the entire shell, and slightly decussates with faint lines of growth. 
The principal keel is a little fretted. 
Fig. 6c.—Specimen from the Lower Calcareous Grit of Cayton 
Bay (Leckenby Collection). As regards the fine striations this is in 
an inferior state of preservation. The anterior keel of the body- 
whorl is perhaps a little stronger than in the other specimen. 
Relations and Distribution—The relations of this species have 
already been partially indicated. Piette observes (op. cit. p. 105) 
that it is distinguished from others of the same genus by the 
prominence of the keels. In France, its head-quarters are in the 
*‘ oolithe ferrugineuse,”’ at Neuvisy, Viel-Saint-Remy, etc. In Ger- 
many Chenopus bispinosus, Phil., is quoted by Brauns (Ob. Jura, 
p. 185), from the Heersumer Schichten (perarmatus-zone) of N.W. 
Germany. 
In Yorkshire A. bispinosa occurs throughout the Lower Calcareous 
Grit, and seems to have been found at Pickering in beds which 
may possibly be as high as the Trigonia-beds at the base of the 
Coralline Oolite. I have never seen a specimen from the Coral Rag. 
Postscript.—There is a good specimen amongst the Kelloway Rock 
fossils in the Museum at York. The spiral angle is slightly closer. 
There is a less sudden increase in the penultimate whorl, whilst the 
keel is a little more towards the middle: the anterior keel of the 
body-whorl is rather stronger than in the Lower Calcareous Grit 
fossil. The ornamentation is similar, and the differences are exceed- 
ingly slight. 
Family Lirrorinipz. 
The shells next to be described were formerly referred to Turbo, 
