82 PREHISTORIC EUROPE. 



cessive, for they are based on the assumption that past climatic 

 conditions did not differ from the present. As we shall see in 

 the sequel, however, this is very far from having been the case, 

 for we have every reason to believe that at certain epochs during 

 the Pleistocene Period the rainfall was considerably greater than 

 it is now. At present the rainfall near Torquay is about 35 

 inches, but in former times it may have been three or four times 

 as much, or even greater still. With a rainfall of 140 inches 

 the stalagmites would accrete, other things being equal, four 

 times as rapidly, so that one inch might form in 1000 years. 

 At that rate the upper stalagmite would require 60,000 and the 

 lower bed 144,000 years respectively for their growth. 



In other parts of the cave, however, we have evidence to 

 show that the stalagmite has sometimes accreted at a more rapid 

 rate. Thus, overlying a superficial layer containing remains of 

 Eomano-Saxon times, we find a thin interrupted cake of stalag- 

 mite which nowhere exceeds six inches in thickness, and is 

 generally much thinner, or absent altogether. Assuming, there- 

 fore, that six inches as a maximum have accreted in 2000 years, 

 and using this comparatively rapid rate as a standard of measure- 

 ment for the older stalagmitic pavements, we should still have a 

 period of 20,000 years for the formation of the upper layer, and 

 of 48,000 years for the lower. But on the supposition that, 

 owing to an excessive rainfall, the stalagmites formerly increased 

 four times more rapidly than they do now, the first period would 

 be reduced to 5000 years, and that of the lower stalagmite to 

 12,000 years. 



We have no grounds, however, for believing that the Pleisto- 

 cene Period was characterised throughout by such an excessively 

 wet climate. I shall have occasion to refer in the sequel to the 

 evidence bearing upon the former occurrence of a rainy climate, 

 and hope to be able to show that a succession of wet and less 

 humid periods alternated during Pleistocene times. Now, 

 although the rainfall in some of those wet periods may have 

 been considerably in excess of what I have supposed merely for 

 the sake of illustration, yet on the other hand it may have come 



