holmes] aboriginal american antiquities part i 53 



2. Traditional (Mnemoxk) 



Data sujiplied by native tradition employed by chronologists neces- 

 sarily with much caution, 



'). Ijiolooical 



(a) Data derived from the growth and decay of forests. 

 (h) Data derived from the distribution of plant species by human 

 agency. 



(c) Data afforded by changes in living forms, as of shellfish, dur- 

 ing the human period. 



(d) Data based on the differentiations of the human groups and 

 on the modification of aniuuil species, as the llama and alpaca, 

 through douiestication. 



4. Cultural 



(a) Data derived from a consideration of the bulk of work ac- 

 complished by the tribes, as in irrigation Avorks, mines, and archi- 

 tectural monuments. 



(h) Data derived from a study of the cidture contents of in- 

 habited sites representing successive occupancies. 



(c) Data furnished l)y a consideration of the tiuie required for 

 the evolution of various branches of culture, as language, customs, 

 arts. 



(d) Data derived from the study of uiigrations and the tiuie re- 

 quired in completing the settlement of the several land areas of the 

 globe. 



5. Geological 



(a) Data derived from the association of traces of man. physical 

 and cultural, with geological formations, a chief resource of the 

 chronologist, association being (1) with the systematic formations; 

 (2) with river terraces, lake beds, eolian accumulations, and cave 

 deposits, the relative, and in a measure, the actual age of which can 

 be determined. 



(h) Data furnished by changes in artifacts by weathering, sand- 

 blast, etc. 



G. Paleoxtological 



Data supplied by association of the remains of man and his works 

 with fossil remains of animal and vegetal life, the geological place 

 of which has been determined. 



7. Mineralogical 



Data based on the rate of alteration Avhich takes place in the 

 material of antiquities and in osseous remains from decay, minerali- 

 zation, and patination. 



