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30 THE EXTLOHATIUN OF THE CAUCASUS
composed of friable crystalline schists. This fact, which, as far as
I know, has not yet been noticed by geologists, has ^'ery important
practical effects. The chain in these portions is without conspicuous
peaks and crests for a few miles, and is travei'sed by relatively
easy and frequented cattle-passes.
The granitic main chain is not accurately described as a single
wall. Nor are the same peaks,
as a rule, conspicuous from the
steppe and the southern lowlands. Dykhtau and Koshtantau are
seen from Piatigorsk on the north, standing out on a bold spur
whicli generally conceals Shkara and Janga. The Adai Khokh
of the Lower Rion, is
group, so conspicuous from the heights
hidden from the north-west by the Bogkhobashi range north of
the Urukh.
The central chain of the Caucasus, when studied in detail,
recalls the features of the Pennine Alps. It consists of a number
of short parallel, or curved horse- shoe ridges, crowned with rocky
peaks and enclosing basins filled by the neves of great glaciers, the
Karagom, the Dykhsu, the Bezingi, the Zanner, and the Leksur. I
name only a few of the greatest.
In its double ridges, with vast
of Mont
frozen reservoirs between them, it resembles the group
like those of the Saasgrat and the
Blanc ; it has lofty spurs,
Weisshorn. On either side of the main chain the same succession
is repeated, with one important difference. On the north the schists
come first, sometimes rising into peaks and ridges in a state of
ruin most dangerous to climbers— a fact indelibly impressed on my
then the limestone
memoi'y — but more ofteiT worn to rolling downs ;
range — writing-desk mountains that turn their steep
fronts to the
central snows ; lastly, low cretaceous foothills, that sink softly into
the steppe. But on the south side the crystalline rocks are
succeeded by a broad belt of slates, as to the age of which the
evidence is at present conflicting and the opinion of geologists
divided.'
East of Adai Khokh, by what seems a strange freak of nature, the
granitic range is rent over and over again to its base by gorges, the
1 See Professor Bonney's Note to the Geological IMap, Vol. ii. Appendix A.