310 PHYSIOGRAPHY OF CENTRAL-ASIAN DESERTS AND OASES. 
There is, therefore, reason to believe that at one time the famous way from 
China to Bactria lay along the Alai valley and past Hissar, which city may have 
owed its importance to it. Moreover, there is a well-engineered trail from Hissar 
over the Mura Pass to Samarkand, and another one to Bokhara or Pai-kent, which 
would make at Hissar a point of intersection of three important routes. This 
would not interfere with the idea that direct communication between Bactra and 
Samarkand took place via the Iron Door. Perhaps it varied with the attitude of 
intervening people. And the Tash Kurgan route over the Southern Pamir may 
have been used for communication between Southern Bactria and China, while 
the more important trade of Bactra itself passed direct by way of the Alai valley. 

Fig. 472.—Ruins of the Tomb of Bibi Khanum (Samarkand). 
OASES OF THE ZERAFSHAN. 
RIVER-BANK (TYPE II) OASES OF THE LOWER ZERAFSHAN. 
Having been a river fed almost exclusively by glaciers for all archeological 
time, the Zerafshan has necessarily given a fairly constant supply of water—that 
is, its oases were never affected by the sudden droughts and minor oscillations of 
precipitation that ever and anon wrought famine to oases depending on streams 
fed by unconsolidated snow or rain. 
Everywhere along its lower course and beyond the limits of its now living 
oases, rise the mound remnants of past civilization. From Paikent to Samarkand 
is a land no less favored than the long stretch of the Jaxartes where there was an 
unbroken belt of gardens, of whose houses it is said the roofs were so joined through 
continuous villages of covered-over lanes that a cat might find his way throughout 
and never come to ground. Even now, for 200 miles along the Zerafshan it is 
mostly oasis, though crept upon by intervening deserts, and still stands unparal- 
leled in Central Asia. Such a gifted land was naturally preyed upon by the 
plundering hordes that ranged the steppes of Asia from Manchuria to the Caspian, 
and enters history as a goal of conquering armies. Even now the story-tellers of 
