2 SUPPLEMENT TO THE CRAG MOLLUSCA. 



GASTEROPODA. 



PULMONATA. 



Helix Suttonensis, S. Wood. Tab. I, fig. 2, a — c. 



Spec. Char. H. Testa aperte umbilicatd, orbiculatd, supra convexiusculd, costulato -trans- 

 verse striata, subttis convexd, laevigata ; anfractibus septem subcarinatis, versus peri- 

 pheriam inconspicue subangulatis ; aperturd angustato-lunulatd ; peristomate rejlexo ? 

 umbilico parvo. 



Diameter, \ of an inch. 



Locality. Coralline Crag, Sutton. 



A single specimen rewarded ray researches in 1867, and this is the first in- 

 stance, so far as I know, of a land animal having been observed in the truly marine 

 deposit of the Coralline Crag. This deposit I have always imagined to have been quite out 

 of the reach of fresh-water streams, and the only way I can account for the presence of this 

 Helix at Sutton is that it was probably carried out to sea upon a piece of drift wood, 

 which, in its decay, left it among the marine Mollusca. 



This is an elegant little shell, and symmetrical in its form. It has seven volutions, 

 the first of which is perfectly smooth, but the others are beautifully ornamented with 

 thickened and rounded, but not imbricated, ridges, or thickened lines of increase ; about 

 eighty on the outer volution, and the suture or juncture between the whorls is deep and 

 very distinct, the edge of the succeeding volution being slightly elevated. The under 

 surface of the shell is quite smooth, the umbilicus small, and broadly funnel-shaped. 



On comparing my fossil with existing species I find it most nearly related to Helix 

 calathus and H. bifrons, but to neither of them can it be strictly referred ; the spire is less 

 elevated than in the first, but more so than in the second, and there is a difference in the 

 ornamental ridges of both ; in one they are fewer and larger, and in the other smaller. 

 In my shell the umbilicus is more funnel-shaped, and as ray specimen was probably a 

 full grown individual, judging from a slightly reflected margin to the aperture, it is not so 

 large as either of the recent species ; it bears rather a closer resemblance to bifrons, but a 

 specimen of that species of corresponding size to the Crag shell has only six volutions. I 

 have therefore given to it the above name to commemorate a locality that has yielded me 

 so many Crag species. 



The near relationship of the shell to Madeira species is not without its significance on 

 the subject of the climate of the Coralline Crag period in Britain, for though a suite of 

 land Mollusca would be necessary before any just inference could be drawn on this point, 

 yet this solitary form harmonises with what I and Messrs. Forbes and Hanley (in opposi- 

 tion to the author of the ' Brit. Conch.') hold to be the general facies of the Cor. Crag 

 Fauna, viz. that it is more southern than British. 



