412 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1936 



would be foolish to suppose that the motives of prehistoric Indians 

 were not sometimes equally trivial. It is a safe guess that a large 

 number of petroglyphs were produced by persons amusing themselves 

 during dull hours. 



Many pre-Columbian petroglyphs, however, must have been made 

 for some definite and important reason, else the designs of each area 

 should not conform in such large degree to a prevailing style and 

 they would not have been worth the immense labor often required 

 to make them. Adherents of the "serious purpose" school, however, 

 frequently err in reading a fiictitious unity into all the glyphs on a 

 single stone. Serious or not, there is little question that a great 

 many, if not most, of the complex petroglyphs are composite in origin, 

 consisting of elements added from time to time by persons who were 

 probably inspired by the original design (pi. 9, A). Irregular ar- 

 rangement and superimposition of figures prove this. Probably 

 very few are the expression of a single vast concept. 



The testimony of modern Indians concerning petroglyphs is ex- 

 traordinarily disappointing. They know of them as landmarks and 

 sometimes believe them to have had a supernatural origin. But even 

 where there is good evidence that the glyphs were made by the tribes 

 now inhabiting the area, the practice seems generally to have been 

 abandoned at the advent of the white man and most knowledge of 

 them promptly lost. The explanation of this is undoubtedly that 

 they were generally of interest only to the persons who made them 

 and the knowledge died with these persons. There is, however, 

 seldom assurance that petroglyphs were made by members of the 

 cultural or linguistic groups now in the area. Nevertheless, a thor- 

 ough knowledge of modern Indians gives many clues to petroglyphs 

 and sometimes accurate interpretation. 



Many though by no mean all petroglyphs were made for religious 

 purposes. Primitive peoples believe the world to be filled with super- 

 natural forces which must be supplicated, placated, or taken into 

 account in some other way at every turn. These forces and spirits are 

 often made more objective through pictures and symbols. A god 

 may be more successfully supplicated if his likeness is present. A 

 supernatural guardian spirit, which has appeared in a dream to some 

 person to offer its aid, will seem more real if one has a tangible sym- 

 bol of its presence. Ceremonies and rites are more satisfying if there 

 is visible evidence of the supernatural forces with which it is con- 

 cerned. People, therefore, make wooden and clay images, altars, 

 altar paraphernalia, sacred dress, insignia, and regalia, and, not in- 

 frequently, pictorial and symbolical representations on stone. 



There is, however, no general explanation of religious art and 

 symbolism. Among ancient Indians as among modern Indians, each 



