INTRODUCTION. Xlil 
near Castle Cary, found the following species, all of which 
were obviously of great antiquity : 
Hygromia hispida, Linné. 
Hygromia rufescens, Pennant. 
Helix hortensis, Miiller. 
Cochlicopa lubrica, Miiller. 
Ancylus fluviatilis, Miller. 
Bithynia tentaculata, Linné. 
Valvata piscinalis, Miller. 
Pisidium amnicum, JMiiller. 
A paper by Mr. Herbert Bolton, r.r.s.e., Curator of the 
Bristol Museum, on the Occurrence of a Shell-bearing Gravel 
at Dunball Island, was published in the Proceedings of the 
Bristol Naturalists’ Society in 1904. At a depth of about 
24ft. from Ordnance datum, or 44ft. from the surface, a layer 
of sand, mud, and fine gravel, averaging 53{t. in thickness, 
contained the following species, Macoma balthica being the 
dominant : 
LAND AND FRESH-WATER. 
Vitrea cellaria, Miiller (= Hyalinia cellaria, Westerlund). 
Pyramidula rotundata, Jiller. 
Hygromia hispida, Linné. 
Vallonia pulchella, Miller. 
Helix hortensis, JJiiller. 
Cochlicopa lubrica, Miiller. 
Succinea putris, Linn?. 
Ancylus fluviatilis, d/iiller. 
Limnza peregra, Miller. 
Planorbis albus, JMiiller. 
Planorbis glaber, Jeffreys. 
Planorbis umbilicatus, Miiller. 
Paludestrina stagnalis, Baster (= Hydrobia ulve, Pennant). 
Bithynia tentaculata, Linné. 
Bithynia leachi, Sheppard. 
Valvata piscinalis, Miller. 
