A CENTUEY OF GEOLOGY. 279 



ANTIQUITY AND ORIGIN OF MAN. 



Even after the great antiquity of the earth and its origin and devel- 

 opment by a natural process were generally accepted, still man was 

 believed, even by the most competent geologists, to have appeared only 

 a few thousand years ago. The change from this old view took place 

 in the last half of the present century, viz, about 1S59, and, coming 

 almost simultaneously with the publication of Darwin's Origin of 

 Species, prepared the scientific mind for entertaining, at least, the 

 idea of man's origin by a natural process of evolution. 



Evidences of the work of man— Hint implements, associated with the 

 bones of extinct animals and therefore showing much greater age than 

 usually accepted — had been reported from time to time, notably those 

 found in the river Somme by Boucher de Perthes. But the prejudice 

 against such antiquity was so strong that geologists with one accord, 

 and without examination, pooh-poohed all such evidence as incredible. 

 It was kSir Joseph Prestwich who, in 1859, first examined them care- 

 fully, and published the proofs that convinced the geological world 

 that earl}' man was indeed contemporaneous with the extinct animals 

 of the Quaternary period, and that the time must have been many 

 times greater than usually allowed. ^ 



Since that time confirmatory evidence has accumulated, and the 

 earliest appearance of man has been pushed back first to the late (irlacial, 

 then to the Middle Glacial, and finally, in Mr. Prestwich's Plateau Grav- 

 els, to the early Glacial or possibly preglacial times. 



Still, however, in every case earliest man was unmistakably man. 

 No links connecting him with other anthropoids had been found. Very 

 recently, however, have been found, by Du Bois, in Java, the skull, 

 teeth, and thigh bone of what seems to ])e a veritable missing link, 

 named by the discoverer Pithecanthropus erectus. The only question 

 that seems to remain is whether it should be regarded as an ape more 

 manlike than an}^ known ape, or a man more apelike than any yet dis- 

 covered. The age of this creature was either latest Pliocene or earliest 

 Quaternary. 



BREAKS IN THE GEOLOGICAL RECORD AND THEIR SIGNIFICANCE. 



From the earliest times of geologic study there ha\e been o))served 

 unconformities of the strata and corresponding changes in the fossil 

 contents. Some of these unconformities are local and the changes of 

 organic forms inconsiderable, but sometimes they are of wider extent 

 and the changes of life system greater. In some cases the unconformity 

 is universal or nearly so, and in such cases we find a complete and 

 apparently sudden change in the fossil contents. It was these universal 



1 Life and Letters of Sir Joseph Prestwich, pp. 124 et seq. 



