RECONNAISSANCE IN CENTRAL TURKESTAN. 169 
THE QUATERNARY UPLIFT. 
The first process which belongs to recent or Quaternary geological historj- 
was a vast uplifting of the Tertiary peneplain, the area of the uplift probably 
extending considerably outside the limits of the region which we are now studying. 
Coupled with the uplifting of the peneplain as a whole, there was a warping by 
which it was deformed into basins, large and small, with intervening swells or 
ridges. As far as was observed, this warping does not seem to have initiated 
new lines of stress, but to have confirmed old ones of Tertiary age. In the old 
movements faulting took place abimdantly ; in the new movements warping was 
the nde and faulting took place rarely. The Quaternary- basins seem to be revivals of 
fonner basins, first formed early enough to receive Tertiary deposits, for the Tertiarj- 
strata usually appear to have been deposited in basins similar to those which they 
now occupy, but less deep; that is, the strata are thickest in the center and grow 
thinner toward the edges, where also they are more warped, as though the edges of 
the basins had been gradually raised out of the area of deposition. The scale of the 
Quaternary warping was large, for some of the ridges, such as the main crests of the 
Tian Shan plateau and of the Alai range, were raised over 10,000 feet above the 
bottoms of the neighboring basins. The Qtiaternar)' uplift gave to the country the 
general form which it now possesses and divided it into portions which have distinct 
characteristics and may therefore be treated as natural physiographic provinces. 
Consequent Drainage. — Before discussing the provinces separatel)', a few words 
should be said about the drainage and the evidence which it gives regarding the 
condition of the land previous to the Quaternar}- uplift. Throughout Central 
Turkestan the drainage is almost iniiversally consequent upon the Quaternary- 
warping, although in some places where the strata are soft the beginnings of a 
subsequent drainage are seen in process of development. The main streams follow- 
the axes of the basins parallel to the general strike and lea\'e the basins through 
gorges which seem to be located where the rims of the basins sag. Most of the 
basins contain Mesozoic and Tertiary- strata, and the main streams usually tra\-erse 
these weaker formations, so that from a mere inspection of a geological map they 
might seem to be subsequent. It is in the tributaries that the true consequent 
character is seen, for they flow down the slope of the warped peneplain surface and 
across the strike of both hard and soft strata. In the old age of the country previous 
to the Quaternary' revival the main streams probably followed somewhat the present 
lines ; for most of the basins, as has already been said, had been fonned earlier by the 
down-faulting or folding of blocks of Mesozoic and Tertiary strata during the pre- 
vious times of deformation, and at late maturity many streams must of course have 
searched out the softest formations. The altitude of the peneplain may then have 
amounted to thousands of feet because of its greatest distance from the ocean, but 
it must have been far lower than now. The hard rocks, the granite and the Paleozoic 
limestones, fonned the uplands as they had done for ages and as they do to-day. At 
present there seems to be no sign of an old subsequent drainage in these uplands, a 
fact which indicates that the country- was so far reduced to a peneplain that the 
streams paid little or no attention to structure. 
