| | | | mass of mud suddenly arrested whilst rolling onwards. The terrace stretches from the N. 70° W. to the S. 70° E. ; a direction which seems to indicate that we have here the last surviving fragment, now almost entirely obliterated, of one of the former offshoots of the Akato-tagh, consisting of the same perishable material as the main range of the Akato-tagh itself, which is, as we have seen, only the shadow of a ruin of a mountain-range. The surface at the foot of the terrace, which when seen from above had appeared perfectly level, was just as rough as the surface up above, the only difference being that the irregularities were of a somewhat different shape. At first they were like long tables and benches, with their tops tilted towards the south and consequently their steeper sides facing the north (fig. 237). Here too these superficial layers were generally mere crusts covering hollow spaces, and no matter how thin they were, they almost always bore the weight of our animals. Then another variety of this provoking schor surface succeeded, namely sharp outcropping edges and laminæ, sometimes almost horizontal, at other times sticking straight up (see fig. 240), all consisting of the same hard material, which rings like a brick if a horse chances to knock against it or chip off a corner with its hoof. |
| | | | Fig. 24o. Our attempt to escape from this region had thus proved unsuccessful; and I have no doubt that the same features are characteristic of divers other parts of the basin of Tsajdam. Indeed we were now in the extreme north-western part of Tsajdam, or rather on the border-line between Tsajdam and the kakir valley of Usun-schor. I encountered also precisely this same disagreable conformation in the extreme south-eastern part of Tsajdam in the end of October 1896, whilst travelling between Ova-tögöruk and Tosun-nor, where the only breaks in the hard, rough schor surface were the channels of the Bajan-gol and the Bulungir-gol, and the courses of their numerous affluents and deltaic arms. Our detour was however the means of our making an unexpected discovery, namely a spring in the midst of the flat desert, surrounded by extensive sheets of ice. Just beyond it and on the north was a clay terrace, with a thick bed of good kamisch, and even some tamarisks, which accompanied the outflow of the water in a long dark line. The water here was rather salter than at the preceding spring, the areometer giving a sp. gr. of 1.0218, while its temperature was + o.5°, though this was affected by the immediate proximity of the ice-sheets. Had it not been |
IIIFカラー高解像度
