58 STEPPE FAUNAS AND TEMPERATE 
wooded regions of China to the south-east by mountain 
chains. Through the Dzungarian Gate this area, to 
which the general name of Desert of Gobi or Shamo 
may be given, is continuous with the extensive band of 
steppes which runs through Russian Turkestan to the 
Aral and Caspian seas, is continued through Southern 
Russia in Europe into Hungary, and is bounded to the 
south-west by the plateau of Persia. But uniform con- 
ditions do not reign throughout this great area, which 
shows many alternations of fertility and aridity. Thus 
the snows of the Pamirs water much of Russian Turke- 
stan through the Amu Daria and the Syr Daria, and 
this westerly region as a whole has a much milder 
winter climate than the easterly region, permitting of 
the extension into it of animals really peculiar to the 
southern steppe and desert regions, those characterized 
by the absence of severe winter cold. 
Climatically, as we have seen, the general features of 
the steppes of temperate Asia are the great range of 
temperature, the hot summers and the bitterly cold 
winters, and the small precipitation, which tends to 
occur in late spring or early summer, giving a dry 
winter and a dry summer and autumn, which makes 
the growth of trees virtually impossible. The frequency 
of dry east winds in winter is an important feature in 
checking the growth of perennial plants, except such as 
die down to the ground. As indications of the nature 
of the climate, we may note that at Orenburg the 
mean January temperature is 4° F., and the mean July 
70° F., while the mean annual precipitation is only 17”, 
with a June maximum, but no absolutely dry month. 
Further to the east much lower winter temperatures 
occur ; thus Sven Hedin found temperatures of —17° F. 
in the Tarim basin, and the river here is frozen for three 
