8 BULLETIN 183, UNITED STATES NATIONAL MUSEUM 



aged slightly over 37 inches, with a minimum of 21.5 inches (in 

 1936) and a maximum of 50 inches. Nearly 70 percent of this falls 

 in the six months from April to September, inclusive. In spring 

 and summer there are frequent violent thunderstorms, occasionally 

 acompanied by hail. There is a frost-free gi'owing season of 180 

 days or more, sufficient to insure maturing of the cereal and truck 

 crops. Hot drying winds are uncommon, and prolonged droughts 

 such as have periodically devastated large portions of the western 

 plains are virtually unknown. 



Viewed as the habitat of primitive horticultural peoples, in part 

 dependent upon the results of the chase, the district offered many 

 inducements. The valley of the Missouri, dominated by a capricious 

 river and subject to floods, was too unreliable to invite permanent 

 settlement. But on tributaries such as the Platte, where wide flood- 

 free slopes and benches directly overlook the stream, and to an equal 

 or greater degree on the smaller terrace-bordered creeks, the situation 

 was ideal. Here man could build on the immediate banks close to 

 never-failing supplies of good water; wood, shelter, game, and arable 

 ground were at hand for the taking. A variable but not too trying 

 climate plus a sufficiency of rainfall and extremely fertile soils that 

 retain moisture through the growing season encouraged a settled 

 horticultural manner of living. With all this to offer, it is scarcely to 

 be wondered that the terraces on the attractive side valleys just off 

 the Missouri were freely utilized by prehistoric man. As for the 

 Missouri River, the trench through which it flows may be visualized 

 as primarily a route for trade, travel, and migration — the artery, so 

 to speak, through which mainly flowed the quickening impulses from 

 district to district along its course. 



HISTORICAL AND ETHNIC SETTING 



It is not known at what early date European traders or adventurers 

 first ascended the valley of the lower Missouri. So far as the available 

 documentary evidence shows, however, only hearsay information from 

 the Indians was extant prior to about 1700. Since the last quarter 

 of the seventeenth century the few semipermanent native settlements 

 along the stream appear to have belonged to tribes representing the 

 Dhegiha and Chiwere division of the Siouan stock. Marquette's map 

 of 1673 (Thwaites, 1900, p. 108) shows the Ouchage (Osage) west of 

 a stream doubtless meant to be the Mississippi, with the semess srit 

 (Missouris) to the northwest; the Kansa are located west of the 

 former, southwest of the latter. Delisle, in 1718, placed "les Mis- 

 souris" on the south bank just above the "R. a la Mine," with 

 "les Cansez" above the mouth of the Kansas River and immediately 

 below the confluence of the "Petit Riv. des Cansez" (Independence 



