as a rule rise on the main range, but in many cases on the short spurs that link it with the Bokovoi Khrebet and other subsidiary ranges.
“The central chain of the Caucasus,” writes Mr Douglas W. Freshfield,[1] “consists of a number of short parallel or curved horseshoe ridges, crowned with rocky peaks and enclosing basins filled by the névés of great glaciers. . . . 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 ... but more often worn to rolling downs; then the limestone 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 [main] range is rent over and over again to its base by gorges, the watershed being transferred to the parallel chain of clay slates . . . which has followed it from the Black Sea, attaining on its way the height of 13,400 ft. in the Laila, and limiting the great parallel basins of the Rion, Ingur and Skenis Shali [= Tskhenis-Tskhali] . . .” “At the base of the central core of the chain spread (to the north) broad, smooth, grassy downs, the pastures of the Turk and the Ossete. . . . Their ridges attain to 9000 to 10,000 ft. They are composed of friable crystalline schists. . . . Beyond these schists rises a broken wall of limestone, cleft to the base by gorges, through which flow the mountain torrents, and capped by pale precipitous battlements, which face the central chain at a height of 11,000 to 12,000 ft. Beyond, again, lies a broad furrow, or ‘longitudinal fold,’ as geologists call it, parallel to the ridges, and then rises the last elevation, a belt of low calcareous hills, on which, here and there among the waves of beech forest, purple or blue with distance, a white cliff retains its local colour and shines like a patch of fresh snow. Beyond, once more beyond, spreads the Scythian steppe, not the dead level of Lombardy, but an expanse of long low modulations, which would be reckoned hills in our home counties, seamed by long shining ribbons, which mark the courses of the tributaries of the Terek. . . . Southwards too, immediately under the snows, we find 'crystalline schists,' smooth grassy heights, separated by shallow trenches, which form the lesser undulations of the three basins, the drei Langenhochthäler Imeritiens of Dr Radde. These basins or ‘longitudinal folds’ are enclosed on the south by the long high ridge of dark slates, which extends parallel to the crystalline [main] chain from the neighbourhood of Sukhum-Kale to the Krestovaya Gora [pass of Darial.] Behind this slate crest spreads a confused multitude of hills, Jurassic and Cretaceous in their formation. . . . Their outer edge, distant some 30 to 40 m. from the snows, is marked by a limestone belt, lower and less continuous than that on the north, which frames the gorges of the Rion, and rises in the Kuamli (6352 ft.) and Nakarala (4774 ft.) near Kutais, its best known elevations.”[2] It may be added that, south of the central watershed, the strata, both Mesozoic and Palaeozoic, 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, 1012 m. long, covering an area of 31 sq.m., and descending to 6535 ft. above sea-level; Leksyr, situated south of Adyr-su-bashi, 712 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, 912 m. long, 14 sq.m. in area and reaching down to 5790 ft., the lowest on the north side; Dyevdorak or Devdorak, from Kasbek, 212 m. long, its lower end at 7530 ft.; Khaldeh or Geresho 414 m. long, from Shkara and Janga-tau; Tuyber from Tetnuld, 612 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, and so narrow that there is only just room for the carriage-road and the brawling river Terek side by side. The pass by which this road crosses the main range, farther south, is known as the Krestovaya Gora (Mountain of the Cross) and lies 7805 ft. above sea-level. The Mamison Pass, over which runs the Ossetic military road (made passable for vehicles in 1889) from the Terek (below Vladikavkaz) to Kutais in the valley of the Rion, skirting the eastern foot of the Adai-khokh, lies at an altitude of 9270 ft. and is situated a little south of the main range. Scarce any of the remaining passes in this west-central region are better than mountain paths; horses can traverse the best of them only during a few weeks in the height of summer. They mostly range at altitudes of 9000–12,500 ft., and between the pass of Nakhar in the west and that of Mamison in the east there is not a single pass below 10,000 ft. The best known in this section are the three Baksan passes of Chiper (10,800 and 10,720 ft.), Bassa (9950 ft.) and Donguz-orun (10,490 ft.), south of Elbruz; those of Becho (11,070 ft.), Akh-su (12,465 ft.), Bak (10,220 ft.), Adyr-su (12,305 ft.) and Bezingi (10,090 ft.), between Elbruz and Dykh-tau; and those of Shari-vizk (11,560 ft.), Edena, Pasis-mta or Godivizk (11,270 ft.), Shtulu-vizk (10,860 ft.), Fytnargyn (11,130 ft.), between Dykh-tau and Adai-khokh; the Bakh-fandak (9570 ft.), between Adai-khohk and Kasbek; and the two Karaul passes (11,680 and 11,270 ft.) and Gurdzi-vizk (10,970 ft.), connecting the valley of the Urukh with that of the Rion. The most frequented pass in Svanetia is that of Latpari (9260 ft.), situated in the first of the southern subsidiary ranges mentioned above, and thus connecting the valley of the Ingur with the valley of the Tskhenis-Tskhali.
Flora.—In this section of the range again the southern slopes are clothed with vegetation of remarkable luxuriance and richness, more especially in the region of Svanetia (42°–43° E.). Not only are the plants bigger than they grow in the Alps, but the blossoms are more abundant. Here again forests of Coniferae predominate, especially on the northern and eastern slopes; and the other distinguishing features of the flora are gigantic male ferns (Aspidium filix-mas), Paris incompleta (a member of the Trilliaceae), Usnea or tree-moss, box, holly (Ilex aquifolium), Lilium monadelphum and many of the familiar herbaceous plants which flower in English gardens, though here they grow to an altogether extraordinary size—“monkshoods, Cephalaria, Mulgedia and groundsels, among which men on horseback might play at hide and seek without stooping” (E. Levier). Other prominent species are Campanula, Pyrethrum, aconite, Cephaelis, speedwell, Alchemilla sericea, Centaurea macrocephala, Primula grandis and a species of primrose. And the great height (13,000 ft.) at which the flowering plants blossom is not less remarkable than the great beauty and abundance of the flowers. Species which grow on both the northern and the southern slopes ascend 2000 ft. higher on the latter than on the former. Walnuts grow up to an altitude of 5400 ft., the vine and mulberry up to 3250 ft., the lime and ash to 4000 ft. The forests extend to the upper end of the limestone gorges. Above that the crystalline schists are bare of tree vegetation. The upper limit of arborescent vegetation is considered to run at 7000–7500 ft., of shrubs such as rhododendrons at 8500 ft., and of pasture-lands up to 9000 ft. The principal cultivated varieties of plants in this section are wheat, rye, oats, barley, beans, millet and tobacco.
3. Middle Caucasus: (b) Eastern Part.—In this sub-section, which stretches from Kasbek and the Darial gorge eastwards to
