The Basin of Eastern Persia and Sistan. 
By Ellsworth Huntington, 
Carnegie Research Assistant. 
INTRODUCTION. 
At the beginning of the work of our expedition in Central Asia it became 
evident that the problem of the plnsical changes which ha\-e taken place in the 
Caspian basin since the advent of man is so complicated as to require the work of 
many years for its solution. It also became evident that if the historj- of the chief 
changes could be ascertained in smaller neighboring basins where there was reason 
to suppose that a similar series of events has taken place, the elucidation of the 
Caspian problem would be greatly facilitated. Accordingly, during the summer of 
1903 our attention was turned to Issik Kul and the mountains of Turkestan; and 
later, on the approach of winter, I was dispatched southward to the renrarkable basin 
of Sistan, in Eastern Persia. Not onh- the basin, but the countn,- traversed in 
reaching it, proved to be full of e\idences of very recent changes in physical condi- 
tions, and the time-scale established by their means is applicable in a large degree 
to the Caspian region, for the main line of evidence, the terraced character of 
mountain valleys, is found abundantly in both the Sistan and Caspian basins. 
The records of antiquity and the work of previous explorers make it certain 
that both basins have long been inhabited and that their present sparsely populated 
condition is essentially different from that of the past. The question to be answered 
is whether this condition is due to purely human causes, such as the deca\- of races 
wars, famine, deforestation, and the exhaustion of the soil by prolonged culti\ation 
on the one hand, or whether it is due to physical causes, such as changes of climate, 
the warping of the earth's crust into higher mountains and deeper basins, the natural 
changes of the course and volume of rivers, and the encroachment of sand-dunes 
on the other. Before this can be answered the human histor\- of the countn,- must 
be more carefully elucidated by archeological work and the physical history by 
geographic work. 
In the pursuit of the latter object, under the direction of Professor Davis, the 
problem resolved itself into two parts, namely, the physical historj- of Central Asia 
in recent times as influenced by internal or terrestrial causes, such as the warping 
of mountains and the deepening of basins, and the histor}- as influenced by external 
causes, such as changes of climate. The studies of a year and a half have led me to 
think that while numerous crustal movements furnish al)undant e\idences of the 
earth's internal activity during ver>- recent geological times, most of the movements 
are too ancient to be connected with human history and too local to have produced 
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