236 AXXALS yEW YORK ACADEJIY OF SCIEYCES 



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RelatlTe rp_^„i„ Descent of 

 duration -^^'^'^'^^ snow line- 



U}(its Years Yea)'s Meters 



Postglacial, post- Wtirm hemicycle... 1 20,000 20,000 



IV or WtEM Glaciatiox 1 20,000 40,000 1.200 



3rd or Riss-Wiirm Interglacial Stage. 3 60,000 300,000 



III or Riss Glaciatio:s 1 20.000 120,000 1.250 



2nd or Mindel-Riss Interglacial Stage 12 240.000 360,000 



II or MixDEL Glaciatiox 1 20.000 380,000 1.300 



1st or Giinz-Mindel Interglacial Stage 5 100,000 480.000 



I or Guxz Glaciatiox 1 20,000 520,000 1.200 



The three chief conclusions of Penck are as follows : 



1. If the whole Ice Age extended over a period of 500,000 to 1,000,000 

 years, the Second yery long -^'arm Interglacial Stage, also known as the 

 Mindel-Eiss or Helvetian, is reckoned at more than 200,000 years, while 

 the final relatively short interglacial stage, the Riss-TTiirni, is reckoned 

 at 60.000-100,000 years. 



2. The duration of the Lower Paleolithic culture periods, the pre- 

 Chellean, Chellean and Mousterian, would by this reckoning be much 

 longer than that of the Upper Palgeolithic culture periods, the Aurig- 

 nacian, Solutrean and Magdalenian. Penck estimates that since the be- 

 ginning of Magdalenian times 24,000 years may have elapsed and since 

 its close about 16,000 years. 



3. Compared with these prolonged Palteolithic divisions the Xeolithic 

 Stone and Metal periods have occupied an almost unappreciable length 

 of time. If the beginning of the jN'eolithic lake dwellings is dated about 

 5,000 to 7,000 years ago we estimate that the beginning of the Copper 

 Age in Europe dates back between 3,000 and 3,500 years: in Africa it is 

 much more ancient. 



The human culture stages are arranged above not according to Penck 

 but according to the more recent correlations of Obermaier. Breuil, 

 Schmidt and others. 



GEOLOGIC AGE OF THE CELTUEE STAGES 



The trend of Palseolithic research lately has been to draw all the 

 human culture periods from the pre-Chellean to the Magdalenian closer 

 together and to reduce the time assigned for their evolution. All the 

 French authorities, led by Boule, Cartailhac, Breuil and Obermaier, are 

 now agreed in assigning the earlier Palseolithic cultures, the pre-Chel- 

 lean, Chellean and Acheulean, to the Third Intersrlacial Stasfe and not to 

 the Second. Schmidt has also lately declared himself in favor of this 

 view after a most exhaustive and valuable investigation of this problem. 



