122 



NATURE 



[Dec. 6, 1888 



ridges of the great Central Asian plateau, which are 

 known under the name of Great Khingan in the north, 

 cannot terminate in the latitude of 35". Probably they 

 continue south-west as far as the Himalayas, and so it 

 is most likely that the region of the Upper Yang-tzse- 

 Kiang is filled with mountains running from the south- 

 west to t"he north-east. 



This view is supported by the results of Prjevalsky's 

 exploration. In i83o, when he took from Dzun-zasak a 

 south-western direction, and thus followed the foot of the 

 highlands, he reached the Khara-usu with comparative 

 ease. But when he went southwards and reached the 

 Dy-tchu under the 96th degree of longitude, he could 

 move neither east nor south. In the east he saw the 

 gorges by which the Dy-tchu, which flows south-east, 

 pierces the first of the series of the mountains that 

 accompany the border-ridge. And further south he saw 

 before him the continuation of the same ridge, and 

 obviously could not cross it in an oblique direction. 



All this becomes obvious when one attentively examines 

 the map which accom-anies Prjevalsky's last work. In 

 fact, we see on that map that the two great lines of up- 

 heavals — south-west to north-east, and north-west to south- 

 east — which so distinctly appear in Turkestan, the Cau- 

 casus, and Siberia (the chains running south-west to north- 

 east being more ancient than those which run in the 

 other direction) are as well pronounced in the southern 

 parts of the great Central Asian plateau as they are in its 

 northern and eastern parts. The whole of Central Asia 

 appears, in fact, as a series of plateaus of various heights, 

 which — very much like Bohemia in Europe — are bordered 

 by chains having a direction from either south-west to 

 north-east, or north-west to south-east. ^ 



Although the Expedition failed to reach Lhassa, its 

 observations on the climate, flora, and fauna of Northern 

 Tibet are invaluable. The climate of the region ; its 

 poor vegetation, which has every year only a few days 

 for developing its flowers and seeds, and neverthe- 

 less is strikingly rich in the numbers of its species ; the 

 mixture of Chinese, Himalayan, Tibetan, and Central 

 Asian species which one finds in these highlands,— all 

 this renders the borderlands of Tibet in Prjevalsky's 

 description almost more interesting than the plateau 

 itself. 



We shall only refer to that part of the journey during 

 which the Expedition moved north-westwards from the 

 Dzun-zasak store-house to the small lake Gas, at the foot of 

 the ridges Tsaidam, Garynga,Torai, Columbus, and Marco 

 Polo's, which connect the Altyn-tagh with the yet un- 

 named highlands of the Upper Hoangho. Most interest- 

 ing facts as to the nature of Tsaidam will be found in the 

 chapter devoted to that part of the journey. Prjevalsky's 

 winter excursion from Lake Gas enabled him to obtain 

 an insight into the structure of the border-ridges which 

 separate Northern Tibet from the lower terrace of 

 Tsaidam (9000 feet above the sea). No less than three 

 parallel ridges constitute that border-region. The outer 

 ones are known under the names of Tsaidam, Garynga, 

 and Torai ; but these are not the highest of the series. 

 The highest summits are gathered in the next row of 



'■ See MushketotTs "Turkestan"; also the articles "Siberia," 

 'Turkestan," " Transcaspian," "Transcaucasia," and "Ural," in the 

 ' Encyclopaedia Britannica," and " Asia" in '■ Chamber^' Encyclbpa:dia." 



mountains — the Columbus, Marco Polo's, and Prjevalsky's 

 ridges (this last name has been given to it by the Rus- 

 sian Geographical Society). Behind them there seems 

 to be a third series of ridges, and then begins the plateau 

 (also intersected by several snow-clad ridges), which is 

 not less than 3000 feet higher than the Tsaidam plateau, 

 and thus reaches about 12,000 feet in its lowest depres- 

 sions. Much remains, however, to be explored before we 

 can have a clear idea as to the structure of the mountains 

 which separate Northern Tibet from the Lob-nor depres- 

 sion. Mr. Carey has already cleared up some points, and 

 we may hope that this part of Central Asia — relatively 

 easy to explore — will be well mapped before very long. Let 

 us mention also that on the high plateaus which Prje- 

 valsky visited from Lake Gas he discovered a new species 

 of Ovis, which he named Ovis dalai - lames ; it slightly 

 differs by its horns and coloration from all known species 

 of the same genus. 



Less than 1 50 miles separate Lake Gas from the Lob- 

 nor, and so the Expedition went to that lake, which was 

 reached early in February 1885. There the Expedition 

 stayed fifty days ; and two chapters of the work which 

 we have before us are given to the description of the 

 Lower Tarim and the Lob-nor (which rapidly dries up 

 and becomes a mere marsh), its flora, fauna, and inhabit- 

 ants. Many photographs illustrate these chapters, so 

 that now we have an accurate idea of the nature and 

 inhabitants of the great depnessio.-i which ten years ago 

 was quite unknown. From Lob-nor the Expedition went 

 south-westwards to Khotan, and thus followed the foot of 

 the Altyn-tagh, the Toguz-daban, and the " Russian " ridge, 

 which border the Northern Tibetan terrace on the north- 

 west. The Turkestan oases of Tchertchen, Keria, Niya, 

 and Khotan were thus visited, and again we find much 

 valuable information as to the nature and inhabitants oi 

 the country in the chapters dealing with that part of the 

 journey, as also excellent photographs of the inhabitants. 

 Especially interesting are the photographs of the moving 

 sands with their " ripple-marks " made by the wind, 

 of the gigantic holy willows around a Spring in the 

 oasis of Niya, and of mulberry-trees in Yasulgun. 

 It would be impossible to give in a itvf lines an 

 adequate impression of the information gathered by 

 Prjevalsky during his journey on a relatively beaten tract 

 in Eastern Turkestan. To take one instance, we have 

 hitherto had a general idea of the oasis of Keria and the 

 high border-ridge which separates it in the south from the 

 high plateaus. Although Prjevalsky made only a short ex- 

 cursion in these highlands, he supplies us with a most 

 vivid description of the ridge (nearly 20,000 feet high) and 

 its outer spurs, its flora and fauna, its inhabitants — the 

 mountaineer Matchins who dig their dwellings in the 

 loess which fringes the highlands (a group of such dwell- 

 ings is represented by a photograph)— and their manners 

 and customs. One feature of the highlands of Keria. 

 is especially worthy of note— the great amount of rain 

 which falls on them in June and July. During the 

 twenty-five days (July 10 to August 5) which Prjevalsky 

 spent on the outspurs of the Keria Mountains, at a heighti 

 of from 12,000 to 13,000 feet, it rained and snowed nearly 

 all the time ; the clouds coming from Tibet being con- 

 densed as they reached the high Keria ridge. The water 

 which falls on the loess soil is immediately evaporated 



