CHAP. xii. GEOLOGICAL PRINCIPLES. 131 



no longer live there the mammoth, the woolly rhi- 

 noceros, the wild horse, the cave-bear, the lion, the sabre- 

 toothed tiger, and many others and that he had left be- 

 hind him, in an abundance of rude flint implements, the 

 record of his presence. Before that time geologists, as 

 well as the whole educated world, had accepted the 

 dogma that man only appeared upon the earth when 

 both its physical features and its animal and vegetable 

 forms were exactly as we find them to-day; and this be- 

 lief, resting solely on negative evidence, was so strongly 

 and irrationally maintained that the earlier discoveries 

 could not get a hearing. A careful but enthusiastic 

 French observer, M. Boucher de Perthes, had for many 

 years collected with his own hands, from the great de- 

 posits of old river gravels in the valley of the Somme 

 near Amiens, abundance of large and well-formed flint 

 implements. In 1847 he published an account of them, 

 but nobody believed his statements, till, ten years later, 

 Dr. Falconer, and shortly afterward, Professor Prest- 

 wich and Mr. John Evans, examined the collections and 

 the places where they were found, and were at once con- 

 vinced of their importance; and their testimony led to 

 the general acceptance of the doctrine of the great an- 

 tiquity of the human race. From that time researches 

 on this subject have been carried on by many earnest 

 students, and have opened up a number of altogether 

 new chapters in human history. 



So soon as the main facts were established, many old 

 records of similar discoveries were called to mind, all of 

 which had been ignored or explained away on account of 

 the strong prepossession in favor of the very recent 

 origin of man. In 1715 flint weapons had been found 



