Sec. iii] ALONG THE WESTERN RIM OF THE PAMIRS 855
From here, on August i6th, we clambered up a thousand feet more over very steep rock slopes to the spur of Odiâz-kôtal (Fig. 386). On the north it was flanked by a high ridge of shattered rock which the landslide had carried across from the opposite side of the Bartang valley. On descending from this newly formed pass amidst masses of detritus, I first sighted the narrow fiord-like lake which had been formed in what was before the mouth of the Shedau valley by the same huge barrage as had blocked the Bartang river. A difficult scramble over rock debris scattered in wildest confusion brought us down to the northern end of the Shedau lake (Fig. 372). We had now to pick our way with much trouble along the southern foot of this enormous barrage over jumbled masses of rocks and detritus, until at last we gained the foot of the spur which divides what was the Shedau valley from that leading towards the Langar pass. It was on ascending this spur to the south-east that the full extent of the change wrought by that great cataclysm revealed itself.
The fall of a whole mountain, completely blocking the river, had since February 1911 converted the so-called ` Sàrèz Pamir' 4 into a fine alpine lake (Fig. 374), which already in 1913 was over 17 miles long and had since been spreading up the valley.' Enormous masses of rock and detritus had been shaken down from the range on the north and had been pushed by the impetus of the landslips up the steep spur flanking the mouth of the Shedau valley. The gigantic dam thus formed seemed even then, four years after the great landslide, to rise more than 1,200 feet above the level of the new lake. Fig. 373 shows it as seen from about 1,50o feet above the lake. Stone avalanches were still descending from the scarred mountain side above the barrage and accounted for the clouds of dust which are seen in the photograph (Fig. 373) rising on the uppermost slopes of the mountain.6
At the very foot of the spur above mentioned, in a dismal mud-filled depression, I had the good fortune to find a small Russian party under Professor J. Preobrazhenski just arrived in camp from the side of the Alichur Pamir for a systematic survey of the great barrage. A detailed record of the results of this has since been published by him in the Russian Geological Committee's IWatériaux pour la géologie, &c. (Fasc. 14, Petrograd, 1920). The Russian scientists had arrived by skin raft from the southern extension of the lake, which they had reached across the Langar pass. In the course of their very kindly welcome they expressed their belief that my intended passage with baggage along the precipitous slopes above that inlet would prove impracticable. As, however, the plucky Rôshâni headmen with us were quite prepared to make the attempt, the spur was ascended to a height of about 13,200 feet and camp pitched beyond near a small spring some 600 feet lower.
When next morning a steep descent of some 2,000 feet had brought us down to the dazzling green waters of the Yerkh fiord (Fig. 376), we realized readily enough the difficulties of farther progress along the precipitous rock slopes thrown down by the earthquake and over dangerous debris shoots in many places still liable to move. Fortunately the men collected from the upper-
4 Cf. regarding this misnomer, Curzon, The Pamirs, p. 20. pp. 158 sqq. [The figure of 15o m., p. iox, for the estimated
5 I take this statement from a report on the great earth height of the barrage, seems to be due to an oversight or
quake published by Captain Pultoff in the Transactions of misprint.]
the Geographical Society of Tashkend, 1913, which I had 6 In a paper largely based on a report by Col. Spilko
occasion to see on the spot in the hands of Professor Preobra (Comptes rendus de l'Académie des Sciences, clx. pp. 810 sqq.),
zhenski and to which M. Obrucheff, the distinguished Rus Prince B. Galitzin has expressed the belief that the Sâréz
sian geologist, refers in the Zeitschrift der Gesellschaft für landslide was not the consequence but the cause of the earth-
Erdkunde, 1922, p. 47. The greatest depth of the lake was quake of February 18th, 1911, which many distant seismo-
then estimated at 131 fathoms. logical stations had registered. Evidence against this view
A description of the earthquake results as they presented has been set forth by Mr. R. D. Oldham, F.R.S., in Quart.
themselves in December 1911, when the lake was still com Journal Geolog. Soc., lxxix (1923), pp. 237 sqq.
paratively small, is given in Schultz, Forschungen im Pamir,