288 PHYSIOGRAPHY OF CENTRAL-ASIAN DESERTS AND OASES. 
And, as he goes on to say, the fact that some of the Tian Shan ranges are 
now gashed into more alpine form means that “they were somewhat less worn- 
down in the previous cycle of erosion, or, like the Dongus-tau, already more con- 
sumed (owing to greater uplift or to weaker structure) in the present cycle of 
erosion or both.’’* 
te us 
alt sat - 
Wy 
Se a 
Wl 
| 
a 
\\ 
Hh 


n pi 
il ie tlh) pil ; yi MEN HWS 
Hil MWh { \\ \ me i W wl Bp Ha Araya Be 
Hi Mi ih \\\ < = \\ SMW) Hii i TZ. aa 
HH i ii wee WS Aue \ys Is ‘é Tw’ V4 WN MA 
eee ve 
Till mM bl ¥ LS i Fr gE 
sii ii i piso Ch nk at of : 
yi Hi oe ie 
yt > ‘4% 
:, g \ 
Mr a i 
WA “ sng os ah 
he Zany satis wayuill fie a a va : 
why, AANA Zi 
Z Y : ail ey 
ex Aare SZ ky) 
““ BB 2\ Ve Wa, gs a 
; o \\ Al / 
NS sie ii \ Z gil 
aN 
e 10 ceased 
ae Kurgan ----- Trend of faults 
Fig. 465.—Uptilted Piedmonts of Marghelan. 
In the Fergana basin we have, as already hinted, a remarkably good example 
of the differential earth-movements characteristic of a sinking deposition area 
with uplifting of eroding border ranges. And there, as in the Tarim basin, this 
movement has involved an encroachment of mountains on plains through uptilting 
of their margins. We have seen how, with the Alai Mountains, uplift was periodic 
with intervening times of quiescence, which with the Taldic gave rise to four 
erosion cycles, the first one closing in Central Asia’s peneplain stage, and how 

* Carnegie Institution of Washington Publication No. 26, Explorations in Turkestan, 1903, p. 73. 
