322 Bowman — Geologic Relations of the Cuzco Remains. 



been buried from three to six times longer than the historic 

 period. 



The Scandinavian geologists argue for a much shorter post- 

 glacial period than American geologists have heretofore con- 

 ceded.* Their time estimates, calculated on the basis of the 

 thickness, rate of formation and character of clay and bog 

 deposits, give the post-glacial period a length of 15,000 to 

 20,000 years or less. We have to note of course that their 

 results, based on facts gathered much nearer the center of an 

 old ice field, are not strictly comparable with results from 

 Niagara and the Finger Lakes district, near the edge of the 

 glaciated country. All of these figures should be regarded as 

 rough estimates which express an opinion, or as a calculation 

 with a wide margin of error. 



Conditions of Burial. 



One asks at once how the bones could be preserved for so 

 long a period. We are all familiar with the decayed condition 

 of bones buried for even a short period of 20, 50, or 100 years. 

 The bones of the Cuzco man are distinctly weathered but they 

 do not fall apart. They are so fragile that we broke some of 

 them in excavation though we used great care ; yet they are 

 sufficiently firm, or at least some of them are, to display a 

 clean mark when scratched with the knife. On the whole 

 their comparative freshness is striking in view of a probable 

 age of 20,000 to 40,000 years. On the other hand, it must be 

 remembered that human bones equally well preserved have 

 been recovered from the shell heaps and kitchen-middens of 

 Europe ; that human bones no more decayed than these have 

 been found in far older glacial deposits in France, Switzerland, 

 and England ; and that more important than the question of 

 state of decay is the question of conditions of burial. The 

 position of the bones within the zone of weathering, the char- 

 acter of the material, the climatic conditions, and the state of 

 the bones at the time of burial are all-important considerations 

 which are discussed in the following paragraphs. 



The bones of the Cuzco man, as well as the related verte- 

 brate remains, all show a certain degree of erosion as if they 

 had been for a short time in the grip of a stream. The finer 

 details are wanting and projecting points are moderately worn. 

 The facts that only the projecting points are rounded and the 

 finer detail lost on the more exposed portions and that the 

 amount of erosion is small argues distinctly in favor of \hs fresh- 

 ness of the material at the time of burial. If the bones had 



* See especially the collection of papers published by the International 

 Geological Congress, Stockholm, 1910, under the title : " Die Veranderungen 

 des Klimas seit dem Maximum der letzten Eiszeit." 



