Till-: ORIGIN AND AN'I hji rn OF M 



in t .in. -iit and even to assign the approxi- 



mate years dun:.- \\ lii.-h each was in vogue. The rough 



FIOUBE 29. Flint Implement* of the Acheulian 



stone age and the polished stone age are the popular 

 terms for the stages showing the most striking differences 



in appearance and workmanship. In tiiruiv M. tin- 

 most recent geologic epoch, the Quaternary, is divided 

 into the lower, middle, and upper Quaternary, covering 

 a period of some 750,000 years. It will !> noticed that 



