CHAPTER I. 



EXPLANATORY AND INTRODUCTORY. 



SOMEWHERE in the past, the long ages of the prehuman 

 geologic record join and merge into the human period. 

 The day when the first man stood erect upon the earth 

 and gazed upon a world which had been shaped for 

 him by the preceding periods of the creative work, 

 was the definite beginning of the Modern Period in 

 Geology. If that day could be fixed in the world's 

 calendar, on reaching it the geologist might lay down 

 his hammer and yield the field to the antiquarian and 

 the historian. On that day a world, for long ages the 

 abode of brute creatures, became for the first time the 

 habitation of a rational soul. On it the old and un- 

 varying machinery of nature first became amenable to 

 the action of a conscious, independent earthly agent. 

 On it a new and marvellous power that of human 

 will was introduced upon our planet. No wonder, 

 then, that in our critical and sceptical time, when men 

 are no longer satisfied with traditions, or even with 

 sacred history, questions as to this mysterious meet- 

 ing-place of the past and present should be agitated 



B 



