Helix hispida. 

 Bidimus lubriciis. 

 Pupa marginata. 

 Planorbis complanatus. 



Robert Bell — Land Shells in the Red Crag. 263 



village of Butley, the later beds of the Red Crag appear, and land 

 and freshwater shells are found in small numbers, but still exceed- 

 ingly rare and scattered : they occur in most of the pits of that 

 neighbourhood intermixed with marine mollusca, principally of an 

 arctic and boreal type, and with some American forms of Pletiro- 

 toma, which have not been noticed elsewhere ; but there is no 

 evidence of a freshwater or even estuarine formation here, no shells 

 of that character being present ; there are no Hydrobice, only one 

 Conovulus (pyramidalis), an occasional Periwinkle, Cardtum edide, 

 fairly plentiful but always of marine form, and the whole of the 

 shelly and sandy beds indicate, as Mr. Searles Y. Wood has observed, 

 a foreshore deposit. 



The land and freshwater shells are all of living British species, 

 are generally common in the recent state, and make their appearance 

 in these beds for the first time. They are as follows : — 



Planorbis spirorbis. 

 Limncea palnstris. 



,, truncatulus. 



,, pereger. 



It is observable that all these species have a very wide range, 

 extending through the whole of Europe from north to south, and the 

 Pwpa even into Iceland, so that in character they precisely agree 

 with the whole of the marine fauna found with them, which is un- 

 doubtedly boreal, perhaps nearly arctic, in its general appearance. 



In the older portion of the Red Crag, that is, from most of the 

 pits and sections which occur about the rivers Deben and Orwell, 

 and from Boyton and the cliff at Walton-on-Naze, which seem to be 

 the oldest of all the beds, only one land-shell has been recorded 

 since the specimen of Helix Bysa yf&s described and figured by Mr. 

 Searles Wood in 1848. This shell, which is of the same species, is 

 in the Canhara Collection at the Ipswich Museum, and came from 

 the deep pit at Waldringfield close to the river. Lately, however, 

 some careful work at Walton-on-Naze has resulted in the discovery 

 of three more land shells in the lower beds, which it is desirable to 

 notice, in the hope that future collectors at this well-known section 

 may be able to increase the number. 



With the exception of one fragment, these Helices have all been 

 found in the lower and more tranquilly deposited beds of the Cliff. 

 This portion is mainly composed of fine grey sand or silt, and lies 

 between the London Clay and that band of single valves of Pectmi- 

 culus and Mactra arcuata which occurs about the same horizon in 

 several parts of the cliff; immediately under this band the sand is 

 fi.nest, and the following shells have been found at various times : — 



JJelix Rysa, S. "Wood. 



Kelix lens, Ferassac. Figuredin Eeeve's " Conchologia Iconica," vol. vii. pi. 17S, 



fig. 1221. 

 A small and not quite adult shell was found about three years ago 

 by Mr. Larcher, of King's College, and was at first supposed to be 

 a young specimen of H. Rysa ; unfortunately, in consequence of the 

 death of Mr. G. S. Gibson, of Saffron Walden, in whose collection 

 the type specimen was placed, no comparison with it could be made. 



