i6o 
EXPLORATIONS IN TURKESTAN. 
PLAN OF REPORT. 
Although the main purpose of the reconnai.ssance was the study of the 
ph%siograph\- and Ouateinar\- geologA' of the countn-, some attention was given to 
the records of earlier times. .Accordingly, it is proposed to discuss first the Paleo- 
zoic geology ver>- briefl\ , llitn the Mesozoic and Tertiary geology more at length 
and with some mention of their relation to formations of similar dates in south- 
western United States, and lastly the Quaternary geology, which will be taken up 
with considerable fidlness. Under the last head will be included a discussion of 
the physiographic jiroNinces into which the region is naturally divided and of the 
processes which have been instrumental in producing the present land forms. 
In conclusion, some attention will be devoted to a consideration of the evidence of 
changes of climate during recent geological times and to an attempt to subdivide 
the Quaternary era on the basis of these changes. 
20 40 DO 80 100 
Authors route 
Fig. 120. — Sketch map of Central Turkestan. 
THE PALEOZOIC SERIES. 
In Central Turkestan a single succession of strata is repeated again and again, 
with only slight local modifications. The oldest obser\-ed fonnation is an ancient 
white marble, shot through and through with intrusions of granite. It was noticed 
only in the Alai Mountains in the neighborhood of Kok Su and Karategin. Its 
junction with the overlving formation was not seen, but the contact presumably shows 
an unconfonnity, as a conglomerate near the base of the covering strata contains 
pebbles of the marble. The granite which is intruded into the marble is of much 
later date, for it occurs abundanth' in the Paleozoic series in the ridges of the Tian 
Shan plateau and along the north side of the Alai range. The main body of the 
Paleozoic series is a great thickness of limestones, many of them .slaty, which 
are stated by Tchernachef to be of Devonian and Carboniferous age. They are 
greatly folded and have been penetrated not only by granite intrusions, but also by 
