Shells, 535 



Shells. — A List of Species qf Land and Freshwater Shells 

 collected^ during the Summer of ISS3, at JVitham, Essex, — They 

 are named according to Turton*s excellent Manual, In the 

 river : Cyclas cornea, amnica ; A'nodon cygneus ; Physa fonti- 

 nalis, hypnorum ; Paludina impura,viridis ; Neritina fluviatilis ; 

 A'ncylus fluviatilis. In ponds and ditches : Cyclas lacustris, 

 calyculata ; Mysca pictorum ; Succinea amphibia, oblonga ; 

 Planorbis marginatus, vortex, corneus, contortus, spirorbis; 

 Limn^Lis auricularius, pereger, fragilis, palustris. Brougiit 

 up by floods : Helix pulchella, Bulimus liibricus, Cyclostoma 

 elegans, Vertigo sexdentata, Valvata obtusa. In hedges 

 and gardens : Limacellus Parma ; Helix nemoralis, hortensis, 

 arbustorum, carthusiana, rufescens, caperata, aspersa, erice- 

 torum, nitens, liispida, pura, radiata; Carocolla lapicida; 

 Clausilia rugc^sa ; Bulimus obscurus. Upon the bark of old 

 trees : Balea fragilis. I also found one specimen, a dead one, 

 of a shell very much resembling Paludina similis ; but it had 

 several more whorls, and, consequently, was longer. — J, C, 

 Witham, Essex, March 20. 1834. 



Botany and Geology. — Affinities between Plants and 

 subjacent Rocks, (VI. 335. 424.; VII. 274.) — Mr. Cau- 

 trell (VII. 274.) says that he believes the foxglove (Digitalis 

 purpurea) never grows upon limestone ; and from this I pre- 

 sume that he infers the affinity between geological stratum and 

 botanical productions. Before I refer to the second part of 

 this subject, however, it is necessary that I should say, that 

 here the foxglove grows abundantly upon the limestone. I 

 am situated just on the verge of the great South Wales coal- 

 field : in the hills to the west that coalfield terminates, 

 bounded by a very narrow band of mountain limestone, to 

 this succeeds the old red sandstone, which I call the strata of 

 the district; and a mile or two to the east, the transition 

 limestone shows itself, running nearly north and south, from 

 within a few miles of Caerleon to Clyther House, a distance 

 of about fifteen miles. When I read Mr. CautrelPs remark, 

 I determined to put the fact to the test, and consequently 

 took a day's walk over a part of this limestone district ; and 

 I can now assert, that, in this limestone district (transition 

 limestone), the foxglove grows luxuriantly and abundantly, 

 as it does likewise in every other part of my neighbourhood. 



With regard to the peculiarity of certain botanical pro- 

 ductions to certain geological districts, I think that this must 

 be a matter of some doubt ; at least, the evidence which I at 

 present possess is not sufficient to confirm me in the belief of 

 the fact. For instance, I call my locality the old red sand- 

 stone district ; and, undoubtedly, that rock is the substratum 



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