GEOLOGY. 33 



The southern part of the jilga, particularly south-east of Jaitupa, is lowest, and here a 

 large quantity of pure salt, in small cubical crystals, is collected. The fact that there is such 

 a large quantity of saline matter together with salt swamps in the southern part, seems to 

 prove that this jilga at least, and probably most of the others, had been washed out by the sea 

 and that, while others had gradually, though only partially, drained off the saline matter, this 

 one retained it, because it has at present no outlet. It is in fact a dried-up saline lake, which 

 at some remote time was cut off from the sea, of which it was a fiord. 



A third jilga is south of the Belauti pass and north-east of the Uibulak pass. It is 

 about 8 miles in breadth and the same in length. There are two large water-courses 

 leading to it from the range. On the southern side it is enclosed by Artysh and gravel beds 

 but whether an outlet exists is not known. A southerly outlet very likely exists. 



[Some little information as to the geology of the Thian Shan may be gained from 

 Russian travellers, although, so far as I am aware, no general description of the range has been 

 hitherto attempted by them ; nor, indeed, have the mountains been sufficiently explored to 

 enable its geology to be thoroughly understood. 



With the exception of publications in the Russian language, the only original papers 

 in which the geology of the Thian Shan is treated, so far as I know, are those by Semenoff 

 and Severtzoff, 1 Osten-Sacken's interesting journey across the mountains, from Vernoye to the 

 neighbourhood of Kashghar, 3 affording very little geological information. A very good general 

 resume" of the section across the Thian Shan is given by Professor Suess 3 in a work which 

 has recently appeared on the " Origin of the Alps," in which the geology of various mountain 

 chains is discussed. The following translation will probably serve to give a better idea of the 

 constitution of these mountain ranges than any which I could compile from the same 

 materials. 



After describing Dr. Stoliczka's discoveries, Professor Suess says, referring to the Russian 

 explorers, 



" From these works it appears that these mountains are solely composed of old rocks, stratified and un- 

 stratified. To granite, syenite, and diorite succeed old slates, and then palaeozoic limestones, amongst which 

 the existence of mountain limestone is proved by fossils. The newest formation is Permian (Rothiegende) in 

 the form of red sandstone and conglomerate, locally containing salt and gypsum. A band of red porphyry 

 runs along the northern foot of the most northerly of these chains, the Trans-Ili-Alatau. * 



" No mesozoic or tertiary beds are known to occur ; consequently the succession of strata is nearly the same 

 as in the Kuenluen, and as, according to Richthofen, in a great portion of the Chinese empire. The moun- 

 tains are composed of great folds, the strike of which occasionally corresponds with that of the separate chains. 



" The main chain of the Thian Shan consists, according to Semenoff, of two parallel axes of granite and 

 syenite, the southern of which forms the principal ridge of the mountains, 5 the northern the ridge of a 



1 Semenoff; Erforschungsreise im Innern Asians im Jahre 1857, Pet. Mit., 1858, p 350: Narrative of an exploring expedition 

 from Fort Vernoye to the western shore of Issik-kul Lake, Eastern Turkestan. Jour. Roy. Geogl. Soc., 1869, p. 311. 



Severtzoff: A journey to the western part of the celestial range (Thian Shan), Jour. Eoy. Geogl. Soc., 1870, p. 843 (translated 

 from the Russian). Erforsehung des Thiaa Schan Gebirgssystems, &c., Erganzungshefte No. 42, 43, Pet. Mit., 1875. 



2 Jour. Roy. Geogl. Soc., 1870. p. 250. 



3 Entshehung der Alpen, 1875, pp. 135, 142. 



4 The names adopted for these various mountain chains by Russian and German geographers are cumbrous, and might be 

 simplified with advantage. The Trans-Ili-Alatau is the range just south of Port Vernoye, and is the more northern of two parallel 

 chains north of Lake Issik (Issik-kul). 



5 The main range is considered to be that lying south of Lake Issik. The highest and best marked portion of this main 

 range lies further to the eastward than the meridian of the lake. 



