PLEISTOCENE CAVE-DEPOSITS. 69 



CHAPTEE V. 



CAVE -DEPOSITS OF THE PLEISTOCENE PERIOD. 



Caves of different kinds — Mode of their formation — Absence of Pliocene organic 

 remains in European caves — General character of cave-accumulations — Com- 

 mingling of human relics with remains of extinct mammalia — "Break" 

 between Palaeolithic and Neolithic times — Stalagmite, its formation and rate 

 of growth — Mr. Pengelly's observations on stalagmitic accretion in Kent's 

 Cavern — Stalagmitic growth not continuous — Calcified earth, sand, and 

 gravel in caves — Angular blocks, debris, and breccia in caves — Succession of 

 deposits in Brixham Cave — Professor Prestwich on the geological history of 

 that Cave — Contemporaneity of man and the old mammalia — Extreme anti- 

 quity of Pleistocene Period. 



Having glanced at the general character of the relics of the Old 

 Stone Period, and acquired some knowledge of the various 

 groups of animals which are believed to have been contem- 

 poraneous with our Palaeolithic predecessors, we may now 

 proceed to consider the nature of the evidence upon which that 

 belief is based. With this question is naturally involved that 

 of the antiquity of the deposits in which the Old Stone imple- 

 ments and mammalian remains are entombed. 



These deposits occur very frequently in caves and rock- 

 fissures, and they are also met with covering considerable areas 

 in certain river- valleys, both in this country and the Continent. 

 We shall consider first the evidence supplied by the cave-accu- 

 mulations, after which we shall be better prepared to understand 

 what geologists have to tell us about the ancient fluviatile ac- 

 cumulations of the Pleistocene Period. 



For my purpose it is not necessary to go into the subject of 

 the formation of caves. Most of the large and important caves 

 occur in calcareous strata, those which have been excavated in 



