SECOND YARKAND MISSION. 



syenitic ones. As already mentioned, the rock often has a porphyritic structure, and the 

 felspar becomes pink, instead of white, as, for instance, on the top of the Khardung pass and 

 on the southern slope of the Chang-la, where large fragments are often met without the 

 slightest trace of hornblende. To the north of the last-mentioned pass the syenitic gneiss 

 gradually passes into thick beds of syenite-schist, and this again into chloritic schist, by the 

 hornblende becoming replaced by chlorite, while the other mineral constituents are gradually 

 almost entirely suppressed. The syenitic and chloritic beds alternate with quartzose schists 

 of great thickness. The schistose series of rocks continues from north of the Chang-la to 

 the western end of the Pankong lake, and northwards to the Lankar-la, generally called 

 the Marsemik pass. On the western route Dr. Bellew met similar rocks north of the 

 Khardung pass at the village Khardung, and traced them northwards across the Shayok 

 up the Nubra valley to near the foot of the Sasser pass. 



Intimately connected with the metamorphic schistose series just noticed is a greenish 

 chloritic, partly thin-bedded, partly more massive rock, which very closely resembles a similar 

 rock found about Srinagar. Only in this case certain layers, or portions of it, become often 

 distinctly or even coarsely crystalline, sometimes containing bronzite sparingly disseminated, 

 and thus passing into diallage. This chloritic rock forms the greater part of the left side of the 

 Changchenmo valley, and also occurs south of the Sasser pass. I think we have to look upon 

 this whole series of schistose and chloritic rocks as the representatives of the Silurian formation. 



After crossing the Changchenmo valley to Gogra, we met with a different set of rocks. 

 They are dark, often quite black, shales, alternating with sandstones. Many beds of the 

 latter have a comparatively recent aspect, and are rather micaceous, without the least 

 metamorphic structure, while the shales accompanying them very often exhibit a silky, sub- 

 metamorphic appearance on the planes of fracture. I observed occasionally traces offucoids 

 and other plants in these shales, but no animal fossils. On the Changchenmo route these 

 shaly rocks form the ridge of the Chang-lung pass, as well as the whole of the western 

 portion of the Lingzi-thung ; and they are met again after crossing these high plains and 

 entering the Karakash valley, as far as Shinglung (or Dunglung). On the Karakoram route 

 Dr. Bellew brought specimens of similar rocks from the Mastagh (Karakoram) range itself. 

 There can be but little doubt, judging from similar rocks which I saw in Spiti, and from 

 their geological relation to certain limestones, of which I shall presently speak, that we 

 have in the shaly series the carboniferous formation represented. 



In many localities along the right bank of the Changchenmo river, then at the hot 

 springs north of Gogra, and on the southern side of the Chang-lung pass, we find the carboni- 



Shaly fandstonft. 



a b e Dark shaly sandstone, 



TrTriassic limestone with crinoids, 

 a= Conglomerates, reddish, rather recent looking. 



b=Quartosc sandstone, pale coloured. ^-carboniferous. 



c= Reddish silicious sandstone, coarse and conglomeratic. 



Shaly sandstones. 



Section of rocks at the hot springs of Gogra. 



ferous beds overlain by triassic limestone, which often has the characteristic semi-oolitic 

 structure of the Krol limestone, south of Simla. At Gogra and several other places dolomi. 



