220 THE BASIN OF EASTERN PERSIA AND SISTAN. 
nniforni changes over broad areas. Nevertheless, the purpose of our expedition 
can not be achieved until we possess such a knowledge of the movements of tlie 
earth's crust in Asia during recent geological times as shall enable us with certainty 
to estimate their possible effect upon early man. I have therefore recorded all 
the data on this subject which came under my observation. Moreover, as my 
journey led through an unknown country, I have thought it advi.sable to record 
certain geological facts relating to earlier times. 
In Asia, as in liurope and North America, the main events of that part of 
recent geological time which immediately precedes and includes early man seem to 
have been due to changes of climate. Evidences of this are found abundantly in 
Persia, Transcaspia, and Turkestan. It is therefore of first importance to ascer- 
tain the exact sequence and degree of each change and the dates of the later changes 
in relation to the origin of man, and accordingly the main jjortion of this rejMrt is 
concerned with the evidences of climatic change in Persia, and with an attempt to 
fonn a tentative scheme of the physical history- of the countr>' during Quaternary 
times. The influence of climate, and especially the physiographic results of climatic 
changes in nonglaciated regions, are so little known that it has seemed necessary- to 
devote some attention to a theoretical examination of these questions. Accordingly 
this report is in the main a study of the influence of climate and of climatic change 
in Persia. When this influence is understood, and when the sequence of events 
shall have been clearly made out, we shall be in a position to determine the relation 
of physiography to climate in Persia and to apply our results to the larger problem 
of Western and Central Asia. 
ROUTE. 
Between the high mountains of Central Afghanistan on the east and the fearful 
salt wastes of Eastern Persia on the west lies a dreary region of naked mountain 
range, huge fans of rough gravel, and level basins floored with fine silt. At the 
northern end of this region the Heri Rud, the river of Herat, furnishes life to the 
towns and villages of Herat, Serakhs, and Tejen, while to the south the half-mythical 
Helmund, before losing itself in the immense swamp of the Hamun-i-Sistan, sup- 
ports the inimerous villages of the province of Sistan. Between these two rivers 
the lowlands are absolute deserts, while the uplands above an altitude of 4,000 feet 
are sparsely studded with villages located at the bases of the higher mountains, where 
water can be procured. 
Across this inhospitable region lies the route from Transcaspia to Sistan. (See 
map.) Through the courtesy of General Ussakovsky, governor of the Russian 
pro\ince of Transcaspia, to whom our expedition is indebted for many favors, I 
was allowed to follow the Russo-Persian frontier and to stop at militar>- posts to 
which foreigners are not usually given access. Starting from Askhabad, the capital 
of Transcaspia, November 23, 1903, 1 proceeded eastward along the southern border 
of the province to Serakhs, at the northeastern corner of Persia. There I was 
joined by Mr. V. G. Yanchevetzki, secretary for special affairs to the governor of 
Transcaspia, and the rest of the journey was made in his company. To him, in 
