286 TROPICAL NATURE, AND OTHER ESSAYS. 



for geological discovery, no advance whatever has been 

 made for a considerable number of years in detecting 

 the time or mode of man's origin. The Palaeolithic 

 flint weapons first discovered in the North of France 

 more than thirty years ago, are still the oldest undisputed 

 proofs of man's existence ; and amid the countless relics 

 of a former world that have been brought to light, no 

 evidence of any one of the links that must have con- 

 nected man with the lower animals has yet appeared. 



It is, indeed, well known that negative evidence in 

 geology is of very slender value ; and this is, no doubt, 

 generally the case. The circumstances here are, how- 

 ever, peculiar, for many converging lines of evidence 

 show that, on the theory of development by the same 

 laws which have determined the development of the 

 lower animals, man must be immensely older than any 

 traces of him yet discovered. As this is a point of 

 great interest we must devote a few moments to its 

 consideration. 



1. The most important difference between man and 

 such of the lower animals as most nearly approach him 

 is undoubtedly in the bulk and development of his brain, 

 as indicated by the form and capacity of the cranium. 

 We should therefore anticipate that these earliest races, 

 who were contemporary with the extinct animals and 

 used rude stone weapons, would show a marked de- 

 ficiency in this respect. Yet the oldest known crania 

 (those of the Engis and Cro-Magnon caves) show no 

 marks of degradation. The former does not present so 

 low a type as that of most existing savages, but is (to 

 use the words of Prof. Huxley) " a fair average human 

 skull, which might have belonged to a philosopher, or 



