alaeozoic, are compressed, crumpled,
faulted and frequently overfolded, with their apices pointing to the
south.

_Glaciers._--As a rule the snow-line runs at 9500 to 10,000 ft. on the
northern face and 1000 ft. higher on the southern face. It is estimated
that there are in all over nine hundred glaciers in this section of the
range, and although they often rival those of the Alps in size, they do
not descend generally to such low altitudes as the latter. The best
known are the Bezingi or Ullu, between Dykh-tau and Janga-tau, 10-1/2 m.
long, covering an area of 31 sq.m., and descending to 6535 ft. above
sea-level; Leksyr, situated south of Adyr-su-bashi, 7-1/2 m. long, 19
sq.m. in area, and creeping down to as low as 5690 ft., this being the
lowest point to which any glacier descends on the south side of the
range; Tseya or Zea, descending 6 m. from the Adai-khokh to an altitude
of 6730 ft.; Karagom, from the same mountain, 9-1/2 m. long, 14 sq.m. in
area and reaching down to 5790 ft., the lowest on the north side;
Dyevdorak or Devdorak, from Kasbek, 2-1/2 m. long, its lower end at 7530
ft.; Khaldeh or Geresho 4-1/4 m. long, from Shkara and Janga-tau; Tuyber
from Tetnuld, 6-1/2 m. long, area 21 sq.m., and reaching down to 6565
ft.; Tsanner or Zanner, the same length and the same area, but stopping
short 240 ft. higher, likewise given off by Tetnuld; while between that
peak, Adish and Gestola originates the Adish or Lardkhat glacier, 5 m.
long and terminating at 7450 ft. The total area covered by glaciers in
the central Caucasus is estimated at 625 to 650 sq.m., the longest being
the Maliev on Kasbek, 36 m. long; but according to the investigations of
M. Rossikov several of the largest glaciers are shrinking or
retreating, the Tseya at the rate of something like 40-45 ft. per annum.

_Passes._--It is in this section that the entire mountain system is
narrowest, and here it is that (apart from the "gate" at Derbent close
beside the Caspian) the principal means of communication exist between
north and south, between the steppes of southern Russia and the
highlands of Armenia and Asia Minor. These means of communication are
the passes of Darial and Mamison. Over the former, which lies
immediately east of Kasbek, runs the Georgian military road (made
1811-1864) from Vladikavkaz to Tiflis, cutting through the mountains by
a gorge (8 m. long) of singular beauty, shut in by precipitous mountain
walls nearly 6000 ft. high,