PHYSIOGRAPHIC OBSERVATIONS. I37 
the gravels of branch streams. Kizil-Art pass lies on the middle of a sagging ridge 
between two diametrically opposite back-to-back cirques. The northern one heads 
the Kizil-Art Valley, which a.ssumes, below the cirque, the twice-troughed-valley 
form seen in the Alai \'alley triinitaries. The bench or change of cnrve in this 
valley is bnt imperfect!)- preserved, but is occasionalh' well defined and can be traced 
to within a few versts of Bor Daba (fig. 99). 
The stream rising in the heading cirque of this valley has cut back a gully to 
within 50 feet of the crest at Kizil-Art pass. This gully is about 10 feet deep and 
10 feet wide at the pass, gradually widens downstream, and increases in depth for 
about 10 versts, where the bottom of the inner trough is abotit 100 feet above the 
stream. Here the pitch of the stream suddenh' decreases, as a few versts farther 
down the bottom of the inner trough sinks under the flood plain. 
MORAINES. 
A few versts below Kizil-Art pass we begin to find jjortious of moraine left on 
the inner trough bottom to one side or the other and above the stream. Portions 
of this moraine occur at rare interv^als all the way down to Bor Daba, where the 
Kizil-Art darj'a emerges into the Alai Valley. Here begins a moraine island extend- 
ing over 10 miles transversely into the Alai \'alley. It is not surrounded by water 
except in flood time, when a distributary of the Kizil-Art darya crosses the flood plain 
to the west and joins the neighboring stream from the Mount Kaufmann mass. 
The position of this moraine and the precipitous manner in which its unaltered 
slopes pitch under the stream gravels give it the mimistakable appearance of the 
mere top of a deeph' buried mass beneath. 
Thus the stream waste is filling back into the lower part of the Kizil-Art \'alley, 
having partialh' buried the fresh moraine l>ing in its mouth and covered the inner 
trough bottom for some 7 versts upstream, so that, although the base is being 
raised by filling back of waste, the upper half of the stream has not yet recovered 
from some previous lowering of base and is still cutting down on rock bottom. 
The only tributan,- amphitheater which I had occasion to examine in this \-alley 
was that opposite Bor Daba, 4 versts to the west. It contains grass-covered 
moraine of fresh topograph) , with kettle-hole lakes. Its bottom seems to be buried 
beneath the flood plain where it opens into the Kizil-Art or tnink valley. There 
appeared to be a mass of ice hanging on the slope some 2,000 feet above. 
Two of the branch streams of the Kizil-Art dar\'a were seen to head in glaciers. 
These branch streams and their valleys appeared to join confonnabh- the Kizil-Art 
darya and its valle)-. 
The occurrence of moraine in the inner trough of the Kizil-Art Valley and the 
occurrence of the partial!) -buried moraine island where tlie inner trough bottom 
lies buried at t!ie moutli of tlie stream show that the glacial occupation of the inner 
trough was prolaably contemporary witli tlie deposition of the fresli moraine island. 
