TRANSBAIKALIA (sometimes also known as Muria)  , a province of Eastern Siberia, lying E. of Lake Baikal, with the government of Irkutsk on the N.W. and N., the provinces of Amur and Manchuria on the E. and Mongolia on the S . Its area (232,846 sq. m.) is nearly as large as that of Austria-Hungary, but its population does not much exceed half a million . Transbaikalia forms an intermediate link between Siberia, Mongolia and the northern Pacific littoral . The Yablonoi Mountains, which run north-east from the sources of the Keruleii to the bend of the Olekma in 56° N., divide the province into two quite distinct parts; to the west, the upper terrace of the high east Asian plateau, continued from the upper Selenga and the Yenisei (4000 to 5000 ft. high) towards the plateau of the Vitim (3500 to 4000 ft.); and to the east the lower terrace of the same plateau (2800 ft.), forming a continuation of the eastern Gobi . Beginning at Lake Baikal, a valley, deep and broad, penetrates the north-western border-ridge of the plateau, and runs eastward up the river Uda, with an imperceptible gradient, like a gigantic railway cutting enclosed between two steep slopes, and it sends another branch south towards Kiakhta . After having served, through a succession of geological periods, as an outlet for the water and ice which accumulated on the plateau, it is now utilized for the two highways which lead from Lake Baikal a'oross the plateau (scoria 4000 ft.) to the Amur on the east and the Chinese depression on the south . Elsewhere the high and massive border-ridge on the north-western edge of the plateau can be crossed only by difficult footpaths . The border-ridge just mentioned, gapped by the wide ope,sing of the Selenga, runs from south-west to north-east under different names, being known as Khamar-daban (6900 ft.) south of Lake Baikal, and as the Barguzin Mountains (7000 to 8000 ft.) along the east bank of the Barguzin river, while farther north-east it has been described under the names of the South Muya and the Chara Mountains (6000 to 7000 ft.) . Resting its south-east base on the plateau, it descends steeply on the north-west to the lake and to the broad picturesque valleys of the Barguzin, Muya and Chara . Thick forests of larch, fir and cedar clothe the ridge, whose dome-shaped rounded summits (gohsy) rise above the limits of tree vegetation, but do not reach the snow-line (here above 10,000 ft.) . The high plateau itself has the aspect of an undulating table-land, intersected by ranges, which rise some 1500 or 2000 ft. above its surface, and are separated by broad, flat, marshy valleys, traversed by sluggish meandering streams . The better drained valleys have fine meadow lands, while the hills are clothed with forests (almost exclusively of larch and birch) .

Numberless lakes and ponds occur along the river courses .

Tunguses hunt in the forests and meadows, but permanent agricultural settlements are impossible, corn seldom ripening on account of the early frost . The lower parts of the broad, flat valley of the Jida have, however, a few Cossack settlements, and Mongolian shepherds inhabit the elevated grassy valleys about Lake Kosso-gol (5300 ft. above the sea) . Quite different is the lower terrace of the plateau, occupied by the eastern Gobi and the Nerchinsk region, and separated from the upper terrace by the Yablonoi range . This last is the south-eastern border-ridge of the higher terrace . It rises to 8o35 ft. in the Sokhondo peak, but elsewhere its dome-shaped summits do not exceed 5000 or 6000 ft . Numberless lakes, with flat undefined margins, feed streams which join the great north-going rivers or the Amur and the Pacific . Low hills rise above the edge of the plateau, but the slope is abrupt towards the south-east, where the foot-hills of the Yablonoi are nearly 1500 and 2000 ft. lower than on the north-west . Climate, flora and fauna change suddenly as soon as the Yablonoi has been crossed . The Siberian flora gives way to the Daurian flora, and this. is in turn exchanged for the Pacific littoral flora on the Manchurian plains and lowlands . The lower terrace has the character of a steppe, but is intersected by a number of ranges, plications of Silurian and Devonian rocks, all running south-west to north-east, and all containing silver, lead, copper and auriferous sands . Agriculture can be easily carried on in the broad prairies, the only drawbacks being droughts, and frosts in the higher closed valleys of the Nerchinsk or Gazimur Mountains .

The lower terrace is in its turn fringed by a border-ridge--the Great Khingan—which occupies, with reference to the lower terrace, the same position that the Yablonoi does in relation to the upper, and separates Siberia from northern Manchuria . This important ridge does not run from south to north, as represented- on the old maps, but from south-west to north-east it is pierced by the Amur near Aibazin, and joins the

Okhotsk Mountains, which however do not join the Yoblonoi Mountains . The rivers belong to three different systems—the affluents of Lake Baikal, of the Lena and of the Amur . Of the first the Selenga (800 m. long) rises in north-west Mongolia, one of its tributaries (the Egin-gol) being an emissary of Lake Kosso-gol . The Chikoi, Khilok and Uda are its chief tributaries in Transbaikalia . The Barguzin and the upper Angara enter Lake Baikal from the north-east . Of the tributaries of the Lena, the Vitim with its affluents (Karenga, Tsipa, and Muya)-flows on the high plateau through uninhabited regions, as also does the Olekma . The tributaries of the Amur are much more important . The Argun, which at a quite recent epoch received the waters of the Dalai-nor, and thus had the Kerulen for its source, is no longer in communication with the rapidly desiccating Mongolian lake, but has its sources in the Gan, which flows from the Great Khingan Mountains . It is not navigable, but receives the Gazimur and several other streams from the Nerchinsk mining district . The Shilka is formed by the union of the Onon and the Chita rivers, and is navigable from the town of Chita, thus being an important channel to the Amur . Lake Baikal, with an area of 13,200 sq. m .

(nearly equal to that of

Switzerland), extends in a half crescent from south-west to north-east, with a length of nearly 400 m. and a width of 20 to 5o m . Its level is 1,500 ft. above the sea.' The wide delta of the Selenga narrows it in the middle, and renders it shallower in the east than in the west . The other lakes include the Gusinoye and Lake Ba-unt on the Vitim plateau . Many lakes yield common salt . The high plateau is built up of granites, gneisses and syenitcs, overlain by Laurentian schists . Silurian and Devonian marine deposits occur only on the lower terrace . Since that epoch the region has not been under the sea, and only fresh-water Jurassic deposits and coal beds are met with in the depressions . During the Glacial period most of the high terrace and its border ridges were undoubtedly covered with vast glaciers . Volcanic rocks of more recent origin (Mesozoic?) are met with in the north-western border-ridge and on its. slopes, as well as on the Vitim plateau . During the Glacial period the fauna of the lowest parts of Transbaikalia was decidedly 'arctic; while during the Lacustrine or post-Glacial periods this region was dotted over with numberless lakes, the shores, of, which were. inhabited by Neolithic man . Only few traces of these survive, and they are rapidly drying up . Earth-quakes are very frequent on the shores of Lake Baikal, especially at the mouth of the Selenga,' and they extend as far as Irkutsk, Barguzin and Selenginsk; in 1862 an extensive area was submerged by the lake .

Numerous

mineral springs, some of them of high repute, exist all over Transbaikalia . The most important are the hot alkaline springs (130° F.) at Turka, at the mouth of the Barguzin, those of Pogromna on the Uda (very similar to the Seltzer springs), those of Molokova near Chita and those of Darasun in the Nerchinsk district . The climate is, as a whole, exceedingly dry . The winter is cold and dry, the thermometer dropping' as low as — 58° F . But the snow is so trifling that the horses of the Buryats are able to procure food throughout the winter on the steppes, and in the very middle of the winter wheeled vehicles are used all over the west . To the east of the Yablonoi ridge the Nerchinsk district feels the influence of the North Pacific monsoons, and snow falls more thickly, especially in the valleys; but the summer is hot and dry . On the high plateau even the summer is cold, owing .to the altitude and the humidity arising from the marshes, and the soil is frozen to a great depth . At Chita the daily range in summer and spring is sometimes as much as 33° to 46° In the vicinity of Lake Baikal there is a cooler summer; in winter exceedingly deep snow covers the mountains around the lake .2 The estimated population in 1906 was 742,200 . The Russian population is gathered around the mines of the Nerchinsk district, while the steppes are occupied by the Buryats . A string of villages has been planted along the Shilka between Chita and Stryetensk . The valleys of the Uda, the lower Selenga, and especially the Chikoi and the Khilok have been occupied since the beginning of the loth century by Raskolniks, some of whom, living in a condition of prosperity such as is unknown in ' There is uncertainty as to the absolute altitude (see BAIKAL) . ' See Das Klima von Ost-Siberien," by A .

Woyeikow, in Meteorol . Zeitschrift (1884):

Russia proper, rank amongst the finest representatives of the Russian race . The remainder of the steppe of the Uda is occupied by Buryats, while the forests and marshes of the plateau are the hunting grounds of the nomad Tunguses . South of the Khamar-daban the only settled region is the lower valley of the Jida . On the Upper Argun the Cossacks are in features, character, language and manners largely Mongolian . . The Russians along the Chinese frontier constitute a separate voisko or division of the Transbaikal Cossacks . The Buryats number about x8o,000, the Tunguses over 3o,000 . The province is divided into five districts, the chief towns of which are Chita, the capital, Barguzin, Nerchinsk, Selenginsk and Verkhneudinsk . Although a good deal of land has been cleared by the settlers, nearly one-half of the entire area is still covered with forests . The principal varieties are fir, larch, aspen, poplar and birch, with . Abies pectinata in. the north and the cedar in the south . Only about one-third of the surface is adaptable for cultivation, and of that only about one-tenth is actually under tillage .

Agriculture is carried on to a limited extent by the Buryats and in all the Russian settlements; but it prospers only in the valleys of West Transbaikalia, and partly in the Nerchinsk region, while in the steppes of the Argun and Onon even the Russians resort to

pastoral pursuits and trade, or to hunting . Livestock rearing is extensively carried on, especially by the Buryats, but their herds and flocks are often destroyed in great numbers by the snowstorms of spring . Hunting is an important occupation, even with the Russians, many of whom leave their homes in October to spend six weeks in the taiga (forest region) . The fisheries of Lake Baikal and the lower parts of its affluents are important . Enormous quantities of Salmo omul are taken every year; and S. thymalus, S. oxyrhynchus and S. fluviatilis are also taken . Mining, and especially gold mining, is important, but the production of gold has fallen off . Silver mines have only a very small output . Iron mining is gradually developing, and good coal mines are now being worked . Salt is raised from several lakes, and the extraction of Epsom salts has considerably developed . Manufactures, though insignificant, have increased . The trade is chiefly concentrated at Kiakhta . The Cossacks on the frontier traffic in brick-tea, cattle and hides with Mongolia .

The export of furs is of considerable value . Transbaikalia is crossed by the Trans-siberian railway from Mysovaya on Lake Baikal, via Chita, to Stryetensk, and from Kaidalovo, near Chita, to the Mongolian frontier; the latter

section is continued across Manchuria to Vladivostok and Port Arthur . Regular steamer communication has been established along Lake Baikal, not only for the transport of passengers and goods between the two railway stations of Listvinichnoye and Mysovaya, but also with the object of developing the fishing industry, which is of great importance . Steamers ply up the Selenga river as far as Selenginsk, considerable cargoes of tea being transported along this line .