6o EXPLORATIONS IN TURKESTAN. 
irregular partings, carrying a thin deposit of angular stony waste ; it also showed 
faint color bands, nearly horizontal, which were distinctly cut b)- the slopes of the 
spur sides ; hence the valleys were regarded as younger than the loess. If this 
interpretation be correct, there is reason for thinking that the loess of the spurs is 
older than the uplift on the north-bounding fault, by which tlie revival of valley 
erosion was prompted. Evidently, then, this loess deposit ceased accumulating 
long ago, and has since then been much eroded. The fine loess-like deposit of the 
southern part of the Hunger steppe is colored as river-wash on Muhsketof's map. 
Its surface is gently rolling, and the railroad cuts in the swells repeatedly show its 
fine, unifonn texture. Near the mountains on the south it is traversed by the flat- 
floored valleys of dwindling streams, where we saw many cattle pasturing. 
The uplands and loess-capped spurs over the Sankar Valley, and their relation 
to the Hunger steppe, impressed me as particularly well worth a closer stud)'. 
A considerable area of dissected loess was passed after the railroad had crossed 
the Syr on the way to Tashkent. Like the other deposits, this showed every sign 
of having long submitted to normal erosion. Where the S}t swung against it 
there are vertical bluffs lOO feet or more in height. 
LOESS IN FERGANA. 
The interesting ride through the Fergana basin, from Chernyayevo junction, 
on the main line, eastward to the end of the branch line at Andizhan, deser\-es 
mention in this connection, from the striking suggestion that it gave of the 
conditions, fiivorable and unfavorable, for the supply of loess from rivers. At 
various points, as near Posieto\ka, Kokan, and Andizhan, there were extensive 
plains of gravel, washed, from time to time, by the flooded streams from the 
mountains on the south. The plains were usually barren and open to the action of 
the wind. Dunes were sometimes seen upon them. Such surfaces might afford 
much silt fine enough for carriage by the winds, after the floods that bring the silt 
subside. Neighboring areas of fine soil were irrigated and seemed richly productive 
with crops of cotton, wheat, rice, and lucern, with vines and fruit trees, and many 
rows of poplars. Much silk is produced here. It is woven in se\eral of the cities. 
Many cases of cocoons are sent to France. The silt is deposited in the fields by the 
turbid irrigating streams, as well as by the winds, and is protected from the winds 
by the trees and smaller plants. There can be little question that the occupation 
of this basin for many centuries past has caused a considerable deposit of silt on the 
cultivated areas and held it from being swept away to the uplands by the winds. 
If the water were not led about in canals and spread out on delicately terraced fields 
it would nm wild, and much of the silt that is now detained under plant protection 
would be more open to wind transportation from the torrent flood plains. Culti- 
vation thus seems to be distinctly favorable to the deposition of stream-borne silt on 
the valley plains and unfavorable to the deposition of wind-borne loess on the neigh- 
boring uplands. 
