ORIGINS. 141 



therefore, that while the origin of the blood and lan- 

 guages of the Plains cannot be determined, its cultural 

 problem is in a fair way to be solved. Among the most 

 distinctive traits are the sun dance, a camp circle band 

 system, the soldier societies, highly developed ritualistic 

 bundles, a peculiar geometric decorative art, the use of 

 the horse and travois, the skin-covered tipi, the earth 

 lodge, and economic dependence upon the buffalo. 

 Some of these are absolutely confined to the area and 

 though others are found elsewhere they occur as second- 

 ary rather than as primary traits. We may safely 

 conclude, therefore, that the tribes of the Plains at 

 least developed these traits to their present form, if 

 they did not actually invent them. 



Perhaps the most interesting phase of Plains an- 

 thropology is the general diffusion of traits among the 

 many political and linguistic units found therein. 

 Miss Semple favors the theory that a Plains region is 

 the most favorable environment for the diffusion of 

 cultural traits. Whatever may be the fate of this 

 hypothesis, it is clear that among the Indians of the 

 Plains there has been sufficient diffusion to carry many 

 traits over the greater part of the area. That diffusion 

 rather than independent development or convergent 

 evolution is the most satisfactory explanation of this 

 case, may be seen from noting that the various tribes 

 w r ere acquainted with man} r of their neighbors, that in 

 the sign language they had a ready means of inter- 

 communication and that since their discovery the actual 

 diffusion of several traits has been observed by anthro- 

 pologists. 



