EXPLORATIONS IN TURKESTAN.
;;► '` The first traces of floor A are found as long sloping spurs, projecting trans-
versely into the valley below Taldic pass. Extending down the valley, it rapidly broadens out on alluvium-covered terraces, and appears to have emerged on to a waste-
covered piedmont plain, reach-
4 ing to within 25 versts north
of the present Alai range axis.
`"r'` This plain has now been exten-
sively dissected, and remains only in frequent flat-topped hills
figg' p.. capped with horizontally lying
conglomerate and in the sharper
i°• tops of other hills and spurs
°G. and remains in terraces and al-
luvium 3,500 feet above stream at Gulcha. There were higher
hills that rose as residuals from the alluvium covering portions of the level of floor A (fig. i i 2).
Reaching a point about 3 versts down the valley from Taldic pass, the stream emerges abruptly from its torrent gorge into the wide valley at Ak-BusaGa. The accompanying sketch map (fig. i i 5) gives a rough idea of the dimensions of the plain of the valley floor and positions of the main stream and tributary channels at Ak-BusaGa. Here we find a transitional
Vii► i ! state. The trunk stream has
~ r 'ca1e sunk a channel 15 feet deep
through the grass plain and into
alluvial conglomerates, while the
side tributaries pass over falls
Fig. I15.—Map of the Ak-Busa-Ga into their gullies leading to it.
8 P grass plain and stream channels.
Since these falls are some dis-
tance from the plain border, it is evident that these streams have not had time to
>'?'g ► cut back into their respective valleys since the trunk channel was sunk. Passing
down through Ak-Busa-Ga outlet, we find that the grass plain is there higher above