*

ably flat, only a small volcanic peak rising here and there, detached and isolated, through the thick horizontal bone-beds of sandstone and conglomerate which fill up the valley. But in the other districts, the trough is nearly entirely filled up by vast mountains, which occupy in the parallel valley of Ladak the same position as the catenated chains we have described in Kashmir do in the parallel valley of Kashmir; the chain formed by these mountains has been called by Colonel Cunningham the " Tso Moreri" chain, and has been raised to the position of one of the great parallel chains of the Himalaya, but it will best suit our purpose to consider it as an interparallel mass of mountains.

Deosai has been described already. Drass and Kurghyl are covered with volcanic rocks into which the granite of Deosai gradually passes. Mr. Drew tells me that he found near Kurgyl a rock composed exclusively of mica and felspar, graduating into granite. Some specimens I possess from Tashgam, half way between Drass and Kurgyl, are composed of a dark green hornblende which fuses with difficulty and swelling a little before the blow-pipe. Felspar is not conspicuous, but is probably intimately combined with the hornblende. But rocks undoubtedly volcanic are also seen, such as greenstone and amygdaloid. A considerable bed of limestone reposes on the volcanic rocks and appears to be the continuation of the bed seen near Drass. I do not know the age of this limestone. The Drass bed contains fossils which are, I believe, carboniferous, and I have coloured the bed now under consideration, carboniferous, assuming the continuity of the two beds to be true.

Of the mass of hills traversed by the road from Kurgyl to Le I know very little indeed. They are said to consist mostly of slaty rocks capped here and there by conglomerates and grits.

As we near the valley of the Indus in Ladak proper, near the village Kulsi, interesting beds appear. Resting on a hornblende rock or trap is a series of slate, light coloured limestone, conglomerate with rolled boulders of the same limestone, sandstone, shales and The dip is not very great and the several beds appear to conform together. The whole valley of the

dark purple indicated clays.

* Proceedings of the Geological Society of London, page 306.

Upper Indus from Kulsi to Nodmo (and probably further east) appears to be excavated in this formation and the river flows in a fault of it or more probably in the centre of a denuded anticlinal.* The series of rocks (series of Upper Indus Valley) rest, on the North, against the granite of the Kilas Range. Captain G. Austen, to whom I owe these details, estimates it to be at least 3,000 feet thick, and mentions also its appearance in Rodok at the North of the Pang Kong Cho, resting there unconformably on slate. In the limestone layer of this series (about 150 feet thick or more) Captain Austen found a few fossils which he was kind enough to show me. They were very ill-preserved and fragmentary, but appeared to resemble some forms found in the Kothair bed in Kashmir; some cyathophyllides are certainly not to be distinguished from those represented at figures 56 and 57, Plate VII. Another fossil was supposed to be the radical end of a Calamite. To complicate matters, the fossils were declared by paleontologists at home to be cretaceous. The specimens are so bad, that I apprehend that this determination must have rested entirely on the one fossil which I took for a Calamite, and which was regarded, I suppose, as a Hippurite. My own impression is, that the limestone is identical with the Kothair bed of Kashmir, and therefore either the uppermost layer of the carboniferous or perhaps the lowest of the Triassic.

Above this Upper Indus series come the nearly horizontal grits and coarse sandstones which form the flats called in Ladak Chang Tang and Rang. The non-conformity between the Indus Series and the Chang Tang beds is not conspicuous, as that dips at a very low angle and these are nearly horizontal. There is also, I believe, a great similarity of lithological character between the two formations, one being merely the resettlement of the other. I conceive that some difficulty may be experienced occasionally to decide where one formation ends and the other begins. A few mammalian bones have been found in the Chang-tang sandstone, and there is but little doubt that this bed is similar to the sandstone and conglomerate of the Great Thibet plateau to the north of the Niti Pass. These high horizontal plateaux of conglomerate and sandstone are also observed

* A very great number of rivers in the Himalaya run part of their course in the centre of a denuded anticlinal.

in the Afghan mountains, where they are called in Pooshtoo Ragzhie. I have examined some of these ragzhies, of which the plateau of Rushmuk in Waziristan is a good example at an elevation of 7,000 feet, and I feel satisfied of their fluvio-lacustrine origin and of their age being posterior to the final upheaval of the Himalaya and Afghan mountains.*

Zaskar and Rukshu or Rupshu are interesting districts, on account of their lakes, numerous hot springs and borax mines. The country is an elevated labyrinth of mountains and valleys, having a mean height of 15,600 feet. The principal peaks are the Korsok Too (above 20,000 feet) and the Napko Gondo; but there are great many other nameless peaks; the passes are all a good deal above 17,000 feet. In Zaskar we find a great mass of gneiss and schist which appears to be the eastern extension of similar rocks which begin in Suru, and, after entering largely in the formation of the mountains. of the highland of Zaskar, are prolonged eastward into Rukshu, where they graduate into beds of metamorphic slate on which rest fossiliferous rocks. The gneiss, schist, slate and limestone are all stratified and conformable together, and they all dip towards the S. S. W. The limestone appears to be the continuation of the bed of limestone seen in Suru reposing on the gneiss and schist of the foot of the Ser and Mer peaks.

The occurrence of fossils in Rukshu had been noticed by several travellers, but little was satisfactorily known, and to Captain G. Austen is therefore due the credit of having first brought trustworthy fossils from Rukshu, and to him I am indebted for the following details:

Two of the valleys of Rukshu are the Tso Moreri valley and the Pang-po-loomba; they are separated one from the other by the ridge of the Korsok Tso, composed of granitoid rocks and of gneiss and schist. From the Pang- po-loomba (valley) one passes into the valley of the Tsa Rup (river) by the Pang-po-la (pass), towards Zaskar. This Pang-po-loomba (valley) and Pang-po-la (pass) are the localities where fossiliferous beds have been noticed. The

* Col. R. Strachey appears inclined to regard these horizontal beds of the Great Thibet plateau as contemporary of the Siwalik hills and a sea-formation. I believe that both hypotheses are untenable.

whole bottom of the valley is uneven and its southern portion is formed by beds of limestone in which both Captain Austen and Mr. Marcadieu found carboniferous fossils (No. 1.) At the foot of the Pang-po-la the carboniferous becomes covered by a muddy sandstone (No. 2) which is, however, not seen in situ on the northern slope of

Section across the Pang-po-loomba (valley) and Pang-po-la (pass) in Rakshu from a sketch by Captain Godwin Austen (approximate).

the Pang Po, but of which numerous debris fill the ravines. Above this sandstone is found Jurassic limestone (No. 3), all the way to the top of the pass, full of Belemnites, Ammonites, Rhynchonellæ and Terebratulæ. One of the Rhynchonellæ collected there by Captain Austen appears identical with a form very common in the middle Oolite of Sheikh Bodeen in the Punjab.

Having crossed the top of the pass and descending towards the Tsa Rup (river), the same bed of muddy sandstone (apparently) again crops out. It is there interbedded with thin beds of impuro limestone, and in these beds were discovered a great many Belemnites in fine state of preservation. Mr. R. A. C. Austen, to whom the fossils of these parts were forwarded, pronounced some of them to be Liassic, but I do not know whether these liassic forms came from the muddy sandstone bed or from beds inferior to it.

On the other side of the valley of the Tsa Rup, some beds of limestone, much folded and bent, again appear, but they showed no fossils and their age is therefore unknown; they rest against beds of slate much up-tilted and apparently unconformable to the limestone. At the back of the slate is the great mass of the Ser and Mer chain, attaining immense height and crossed by passes above 16,500 feet high.

75. The Tso Moreri is the largest of many salt lakes which form one of the features of Rukshu. It is 14 miles long and more than 15,000 feet above the sca. Its water is very salt and bitter, though Mr. Marcadieu affirms that it contains only one part of saline matter

in 10,000 parts of water; the saline matter is sulphate of soda and sulphate of lime. Another lake, the Karso-Talao, about 6 miles long, is reported by the same gentleman to contain a great deal of chloride of sodium and sulphate of soda, with a little carbonate of lime and carbonate of soda. These two lakes are said to be surrounded by mountains of crystalline rocks, principally mica-schists and granite. But one of the most interesting subjects connected with the geology of Rukshu is the existence of borax in the valley of Puga. The manner in which it occurs as an efflorescence is too well known to require description here, but one cannot but regret that Mr. Marcadieu's report is not more geological; indeed it can only be regarded as chemical, and the geology of the district is still a work to be done. I have never visited Puga, but, from the several descriptions of it I have read, I am satisfied that the borax ground is the bottom of a dried up lake. The analysis of impure borax collected at Puga shows it to contain, besides borax, sulphate of soda, sulphate of lime, chloride of sodium and carbonate of soda. These impurities are precisely the composition of the Kullur salt of the plains of the Punjab and of the saline matter of many hot springs and salt lakes of the Himalaya and the Salt Range, and it appears to me evident enough that the lacustrine mud which fills up the bottom of the Puga valley, is similar to the alluvial deposit of the Punjab. Boracic acid, which probably once rose freely to the surface of a small lake and was deposited in an uncombined state, is now arrested by the bed of lacustrine mud which fills up the fumarole and combines with some of the salts of soda. It appears therefore much to be regretted that an attempt was not made to estimate the thickness of the lacustrine deposit and that a few wells were not sunk into the borax ground and the waters and gases which might have been collected in these wells carefully examined; possibly such researches and experiments might have led the way to an increase of the present supply, and to a system of collecting the borax or boracic acid sufficiently pure not to require refining.

76. In Ladak, Rukshu, Sooroo and Zaskar, no fossils were ever found, as far as I know, older than those of the carboniferous formation. But if we follow the great valley, between the Kailas Range and the Ser and Mer chain towards the S. E. we find, on the other