W. H. Hudleston—The Yorkshire Oolite. 293 
the Coral Rag of St.-Mihiel. No Purpuroid has ever, to my know- 
ledge, been found in any other district of the Corallian Rocks of 
England, and in Yorkshire all the specimens come from a very 
limited area in the Coral Rag of the eastern Howardians.' 
Genus Narroa. 
This genus is by no means well represented in the Yorkshire 
Oolites generally. In the Lower Oolites, from the Dogger to the 
Cornbrash inclusive, the species are very restricted as to numbers, 
and the individuals are usually of moderate size. There is a small 
specimen, which may be a Natica, in the Bean Collection from the 
Lower Calcareous Grit of Cayton Bay, but the genus is absent, so 
far as we know, in the Passage-beds, Lower Limestones, and 
Coralline Oolite (see Stratigraphical Table in the Introduction to 
Corallian Gasteropoda). The Coral Rag of Yorkshire is richer in 
this genus, and I am thus able to illustrate four distinct species. 
Whether in the struggle with the synonymy, unusually oppressive 
in this slightly ornamented genus, I have been tolerably successful 
remains to be seen. Some of the forms figured approach very 
closely to species from the Great Oolite of Minchinhampton. In 
this respect the species of Natica in the two formations present a 
greater similarity than do the species of Purpuroidea. On the other 
hand, whatever names we may adopt, most of the forms can be very 
nearly matched with similar ones described by D’Orbigny from the 
Upper Oxfordian or Corallian. 
3.—Natica Buccrnormpea, Young and Bird, 1828. Plate IX. 
Figs. la. and 1b. 
Nerita (like maxima, Dillwyn), Young and Bird, 1822. Geol. Surv. Yorkshire 
Coast, pl. ix. fig. 2, p. 244. 
Ampullaria buccinoidea, 1828, Young and Bird, op. cit. pl. xi. fig. 2, p. 244. 
Bibliography, etc.—There can be little doubt that this is the shell 
intended by Young and Bird; the figure in the earlier edition is 
slightly the better of the two. The back view alone is given by 
these authors, and the technical description is not very close. In 
the earlier edition the species was alluded to as a Nerita “from the 
Oolite, two inches long and of equal breadth... .. It is a smooth 
shell, except that the body-whorl is marked with the lines of growth, 
and has a few faint striz at the base.” In the edition of 1828, the 
authors, as usual, are less happy in their remarks, but suggest the 
specific name which I have adopted. It is almost impossible to 
doubt that they were referring to the species described by me below, 
and the name given by them, according to the rule of priority, takes 
precedence of all others. 
Phillips does not seem to have noticed the species in any of his 
1 PurpurowEA, sp.—Not figured or described. A specimen distinct from any 
of the previous forms was found by me in the Coral Rag of Langton Wold. It 
has an extremely wide aperture, which impinges on the columellar area. The 
condition of the shell is not favourable for judging of the ornamentation, and I 
merely draw attention to the existence of a form which may some day be found in a 
better state of preservation. 
Murex Haccanensts, Phillips.—There being no certain evidence that this is a 
Corallian form, it is not included amongst the Corallian Gasteropods. 
