134 
EXPLORATIONS IN TURKESTAN. 
Many of the cross-valleys flowing into the Alai Valley from the Trans-Alai 
range had the form of rounded tronghs cut down in the middle by narrower troughs, 
as in fig. 97. The erosion forms obser\^ed low down on the flank of the Trans- 
Alai, bordering the Alai Valley, are cut mainlj- in rather soft rocks, especially in 
partially decomposed gypsiferous series with occasional harder beds of red sandstone. 
i°<»S.OV 
Kor^^o-D- 
<p9.<.Qj°0{?^, 
over-ridi'ng moraine • 
'V'^,?WS<fe??P^5^»x5*old moraine v?"'C?-'';^"OV'<J^,'ii,7„iOw-?P^§B«=n 
Fig. %. — Section of Alai Valley Transverse Moraine. 
Along the southern border of the Alai Valle}- there project rather flat-topped, 
narrow spurs between the valleys coming down from the Trans-Alai. These spurs 
do not descend to the plains on a gradual slope, but are rather abruptly cut off by 
one or more steep slopes which may be called terminal facets. These facets 
appeared to be aligned and to fall into parallel planes or escarpments truncating the 
base of the range. For convenience let us call the plains of this truncation the 
Trans-Alai escarpments. The apparent level of the old broad-trough bottoms lies 
high up on the escarpment. The bottoms of the new lower troughs lie some 50 
feet above the plains where they cut the escarpment and emerge into the Alai Valley. 
In other words, the later troughs cut the escarpment. 
Professor Pumpelh- discovered that on the slope of the western side of the 
Kizil-Art \'alle\-, where it leaves the mountains and empties into the Alai \'alley, 
there are high terraces of the older moraines, which bend around to the west at the 
Fig. 97. — Ideal section o( a " twice-troughed " valley. 
mouth of the valley and form a portion of the spurs mentioned above. The new 
moraine of the Kizil-Art Valley lies as a long island directly in the middle of the 
flood plain and splitting the stream (fig. 98). It is partially buried by the stream 
gravels, but its topography is notabh- fresh, many little kettle-hole lakes occurring 
on it nearly to the level of the flood plain. 
