GEOLOGY. 49 



rest greenish and purplish sandstones and shales, all which rocks are possihly triassic. North 

 of the old palaeozoic formations to the westward volcanic outbursts of very recent date are 

 found, and the remains of old craters are conspicuous ; and beyond these, again, are limestones 

 and slates of undetermined age, the latter occasionally showing signs of metamorphism. 

 Some of the limestones resemble the triassic rocks in character, but no fossils were detected in 

 them. The presence of metamorphic rocks in the ranges north of Kashghar is proved by the 

 occurrence of gneiss pebbles in the gravels derived from the hills. 



It is probable that coal occurs in .places in the carboniferous formation, as specimens 

 brought from the mountains were examined and roughly analysed by Dr. Stoliczka when 

 in Kashghar. 1 Rocks of the carboniferous period are largely developed in Western Turkestan, 

 and coal has been found in several places. 



The plains of Yarkand and Kashghar consist of recent deposits of clay and sand, with 

 occasional ridges of gravel and marly clay. They, doubtless, resemble closely the other great 

 plains of Central Asia, all of which, having no exit, are basins of deposit, and are being 

 gradually raised by the alluvium brought from the surrounding hills by rivers and streams, 

 which dry up and lose themselves on the plains. Towards the edge of all such plains there 

 are immense gravel accumulations, 2 which greatly conceal all the rocks. Below these gravels, 

 all round the edge of the Kashghar plain, there is found a series of clays, sandstones, and con- 

 glomerates, often much disturbed, but evidently not of old date, called by Dr. Stoliczka 

 Artysh beds, from the Artysh valley north of Kashghar, where they are extensively exposed. 

 No fossils were found in them, but their discoverer was inclined to consider them marine. 

 They present a marked resemblance, both in composition and in their position at the base of 

 higher ranges, to the Sub-Himalayan rocks of Northern India, and the molasse of the Alps. 



All of these deposits, and the rocks on the slopes of the hills for some distance from the 

 great plain, are much concealed by an extremely fine unstratified accumulation, precisely similar 

 in character to the loess of the Rhine and Danube, and which is evidently composed of 

 tine dust, deposited by the atmosphere. The air in Eastern Turkestan, as in parts of China, 

 is constantly, during the day, thick from the fine sand raised by the wind ; so much so, that 

 objects at a comparatively short distance are rendered invisible. 



It is evident that there is great similarity in the geology of all the mountains surround- 

 ing the Yarkand basin. So far as they were examined, the prevalent formations were 

 palaeozoic, resting upon gneiss and other metamorphic rocks ; and carboniferous limestones 

 were constantly found largely developed. The only lower mesozoic rocks recognised were of 

 triassic age, but traces of cretaceous beds were found to the south and west, whilst in the 

 mountains north of Kashghar evidence of comparatively recent volcanic eruptions was met 

 with. No representatives of the Jurassic formations of the Himalayas and Western Tibet have 

 hitherto been recognised in this part of Central Asia north of the Karakoram. 



1 Diary for 1st to 13th February. See also Severtzoff : Journal, Eoyal Geological Society, 1870, Vol. XL, pp. 410, &c. I am 

 also indebted to Mr. Hume for a copy of a report by a Russian Engineer officer named Eamanoifsky, in which the occurrence of 

 i-oal in Western Turkestan is described. 



I have described similar deposits in Persia : Quarterly Journal, Geological Society, 1873, Vol. XXIX, p. 493. 



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