666 K. PUMPELLY EVOLUTION OF OASES AND CIVILIZATIONS 



The reaction did not begin until the inflow of water became insuffi- 

 cient to maintain the inland sea at its maximum of expansion. After 

 this came the change to segregation of communities, first into larger 

 groups of loosely connected units, then the breaking up of these into 

 smaller groups. 



Within the wider limits of the region more or less intercourse could 

 exist between the delta oases on some stretches along the piedmont belt, 

 and often still more easily between those on opposite sides of relatively 

 low mountain ranges. The essential condition was a sufficient frequency 

 of springs or streams to permit travel on foot. 



Under such conditions, continued through thousands of years, the 

 related peoples becoming isolated, in oases and oasis groups, would dif- 

 ferentiate, each evolving its own culture along lines influenced by in- 

 herited traditions, environment, and racial character. 



The development would in general, on account of the isolation, be 

 peaceful, and, while alone and uninterrupted, would lack the benefit of 

 acquisition of the new factors that come with intercourse with unrelated 

 peoples. 



The growth of population on these restricted areas was necessarily 

 accompanied by evolution in social organization. We find the people 

 living in towns, and the long continuance of life under individual town 

 government, practically without external relations, while developing 

 great individuality, must have given the many peoples thus situated cer- 

 tain fundamental political characteristics common to all. 



In the same way, in so far as the physical environment was similar, 

 certain classes of customs, arts, and occupations must have evolved along 

 similar lines. 



In so far as the peoples of larger or minor groups of oases differen- 

 tiated from the same stock or from the same language stock, their lan- 

 guages would retain traces of the original generalized speech. 



All these are ethnographic data to be carefully searched for in sifting 

 and analyzing the results of future investigations. 



It is certain that during this physiographic condition of the region 

 in question, before the domestication of the horse and camel, there could 

 be no movement of population, nor of organized bodies of men, nor of 

 individual across the broader-limiting deserts or waterless steppes. 



There are, however, several data among our finds from this earliest 

 Anau culture which show that a certain amount of intercourse existed 

 with other parts of the oasis-world. Turquoise beads, which occur as 

 burial gifts with the skeleton of a child, must have come from Persia, 



