Having forded this stream, we travelled on towards the south-east, having on our left a low ridge of mire and débris similar to that of Camp No. XXIV, and evidently belonging to the same system of hills. On the right, but at a greater distance, was another similar ridge of a red colour. Between the two there was at first a shallow eroded channel, which gathered into itself all the small rivulets and brooks that we crossed over; and at Camp No. XXV it joined itself to the stream there. Thus here the brooks flow towards the north-west, but farther on they run towards the south-west, and then make their way into another principal stream which likewise has hills on its left bank. Possibly it has a more westerly or west-northwesterly course; it appears to originate in a couple of pools.
The country here, when seen from a distance, wore a particularly inviting and attractive appearance, undulating in long sweeping curves scarcely noticeable, and with an insignificant general rise, and no difficult mountains to impede the view, so far as the clouds would permit us to see. And yet the surface was every bit as abominable as on the miry mountain: it was as soft and spongy as a morass, and consisted of fine yellow plastic clay and mud. Owing to the débris on the top, it wore a deceitful appearance of being able to bear, and yet the animals sank in a foot deep. When the conditions are especially favourable they do not go in more than I dm., and the footprint becomes a dark gaping hole; but as a general rule the footprints of the animals fill up again with the soft porridge-like mire and two or three minutes later can be no longer distinguished. Nowhere was there a square foot of dry ground; it was all saturated, miry, a veritable slough of despond. Whilst travelling along the latitudinal valley immediately south of the Arka-tagh in 1896 I did indeed come across similar boggy ground, though nothing at all comparable to this that I have just described. Possibly the time of year may have had something to do with it. In 1896 it was the end of August and beginning of September when I was in that part of Tibet. Thus it was not very much later; but then in those regions the summer is short, the frost hardly gets out of the ground before April. Probably some parts of the region are further advanced in disintegration and saturation than other parts, and the downfall varies from year to year, while its amount also may be unequally distributed over the different districts. One thing however is evident, namely that the northern boundary of this hateful country is the Arka-tagh. There are it is true boggy tracts in the basin of the Kum-köl, but they are neither so dangerous nor yet so extensive in area but that they can be avoided without any very great loss of time. The peculiar quagmire region which I have described begins only on the south side of the Arka-tagh, in precisely those regions in which the self-contained drainage-basins form a sort of mosaic, and the levelling and filling up of these basins has advanced so far that the surface is flat, and erosion no longer works with concentrated energy. In the flatter parts of these self-contained basins the fall is so insignificant that the running water no longer possesses any decided power of erosion, but, as I have already said, is sucked up by the ground just where it falls. Among the subsidiary ranges on the north side of the Arka-tagh the erosion is peripheral and more energetic.
As we proceeded south-east, we still continued to be accompanied on the left by the same low miry ridge. Its slopes were furrowed, not however by ordinary rain-
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