105 



NOTES ON THE MOLLUSCA FEOM A RAINWASH AT DARENTH, 



KENT. 



By A. S. Kennard. 



Read Ufh March, 1896. 



DcTRiNG the winter of 1894-5 extensive excavations were carried on 

 ; in the parish of Darenth, resulting in the exposure of the remains of 



a large Roman huildiug, which had heen covered since its desertion 

 'by a rain wash varying in thickness from two to six feet. Out of this 



rainwash I have obtained fifteen species of Mollusca, viz. — 



I Amalia Sowerhyi, Fer. 



\ Vitrea cellaria, Miill. 



j ,, nitidula, Drap. 



' Pyramidula rotundata, !Mull. 



HeUcella ericetonim, Miill. 

 ,, caperata, Mont. 

 I Sygromia hispida, Linn. 



' Vallonia pulchella, Miill. 



Helicigona arbuxtoncm, Linn. 



Helix aspersa, Miill. 

 J ,, nemoralis, Linn. 



Clausilia bidetdata, Strom. 

 J Cochlicopa lubrica, Miill. 



CcccilianeUa acicula, Miill. 



Cyclostoma elegans, Miill. 



With the exception of Helix anpersa and H. nemoralis, all the examples 

 u^ere obtained fi'om one spot at the base of the deposit, and were 

 aiixcd with fragments of bone and Roman pottery. Helix aspersa and 

 I H. nemoralis, however, were much more abundant, and always occurred 

 at the very base ; the upper portion of the rainwash contained no 

 ! shells. There can be no doubt that the above list represents 

 the molluscan fauna of the immediate neighbourhood at the period 

 immediately subsequent to the Roman occupation, and on comparing 

 jit with the existing species a difference is at once seen. All the 

 species enumerated are now living in the vicinity; but, on the other 

 aand, there are four species which, though extremely abundant at 

 '.he present time, are entirely absent in the deposit, viz., Hygromia 

 "•ufescens, Helix horteyisis, HeUcella cantiana, and H. virgata. The 

 libsence of the first-ramed is due, probably, to local causes, since it 

 )ccurs at Copford, Crossness, and elsewhere. Helix hortensis is not 

 ^ mown to occur in any deposit, though often erroneously recorded, and 

 I n this case there is no possibility of confounding it with Helix nemoralis, 

 j because all the examples retain their coloration. The past distribution 

 >f HeUcella virgata is rather puzzling. It is entirely absent from 



VOL. II. — OCTOBER, 1896. S 



