OeoJogical Society. 59 



marine deposit remanie from older beds of glacial age, but was 

 itself postglacial and of approximately the same date as the St.- 

 Asapb drift ; in confirmation of which he gave the following list of 

 shells from that drift outside the cave : — Ostrea edulis, Pecten 

 varius, Mytilus edulis, Cardium ecJiinatum, C. edule, Cyprina 

 islandica, Astarte borealis, A. sulcata, A. var., Yeiius f/allina, 

 Tellina hcdthica, Psammobia ferroensis, Mya iruncata, Fissurella 

 grceca, Littorlna littorea, Turritella terebra, and Buccinum undatum ; 

 pointing out that there was only the one species of Astarte among 

 them which was not common on the adjoining coast, just as there 

 were in the older postglacial river-gravels of the S.E. of England 

 two locally extinct forms, the Corbicida jluminalis and the Unio 

 littoralis, and discussing various difficulties, strati graphical and 

 palteontological, in the way of accepting the view that the cave- 

 deposits were glacial, interglacial, or preglacial. For instance, he 

 remarked that there were no marks of glaciation on the face of i he rock 

 in which the cave occurred ; that the cave-deposits were like drift 

 because derived from it, but that no continuity existed between the 

 drift and the cave-deposits ; that there was a much greater thickness 

 of rain-wash and resorted marine-drift looped down over the upper 

 opening into the cave than over the adjoining surface. The upper 

 part of this resorted drift is exactly similar to the material which 

 had accumulated against the old fence, the very existence of which 

 had been denied. The swallow-hole action to which he referred 

 the phenomena was proved by the opened fissures and vertical 

 cylindrical holes in the limestone and by the occurrence of a land- 

 shell (Zonites celJarius). He held that there had been a break- 

 down of the roof and wall of the cave under the drift, and that 

 angular masses of limestone, due to this cause, were found all along 

 in front of the upper opening to the cave. Xo bones were found 

 outside that barrier, there being no bones in the shell-bed and 

 no shells in the bone-bed except the land-shell washed down through 

 a fissure. 



Instead, therefore, of the difficult task of proving that there were 

 in the district many well-known processes connected with subter- 

 ranean denudations, which might explain the superposition of the 

 marine drift upon the bone-earth, each of which had played a part 

 in producing the results observed, he maintained that we had now 

 the clearest evidence as to the exact manner in which it was all 

 brought about, namely, that the marine drift was deposited before 

 the occupation of the cave by the animals whose remains have been 

 found in it ; that at the time of the occupation of the cave the 

 upper opening now seen did not exist, but the animals got in by 

 the other entrance ; that against the wall of the cave where it 

 approached most nearly to the face of the cliff the drift lay thick 

 as we now see it ; that by swallow-hole action the cave was first 

 partially filled, and then the thinnest portion of its wall gave way 

 gradually, burying the bone-earth below it, and letting down 

 some of the drift above it, so that some of it now looks as if it might 

 have been laid down by the sea upon preexisting cave-deposits. 



