The hard calcareous conglomerates are, I think, of different origin from the clayey ones. Indeed, I was induced to believe from what I saw in the neighbourhood of Sungnam, and occasionally in other districts (as I shall have again occasion to notice), that the calcareous conglomerates, which only occur in the neighbourhood of the limestone formation, and therefore where calcareous springs are common, are formed by the infiltration of water containing lime among beds of loose shingle which have accumulated along the base of the steep hills. These calcareous conglomerates are quite local, never very extensive, and are often covered with an incrustation of lime, showing the continued existence of the calcareous springs, by the action of which I suppose them to have been formed.
ALLUVIAL CONGLOMERATE.
August, 1847.
The clay beds, on the other hand, are continuous and uniform in appearance. They vary much in thickness, but are on the whole much thicker and more remarkable in the upper part of the ravine, where (on the east side) a mass of clay, not less than five or six hundred feet in thickness, has accumulated, forming steep sloping or quite perpendicular banks, which at the top are worn away into pinnacles, and excavated into deep grooves and hollows, I presume by the action of melting snow. The fragments of rock which it contained were all angular, or at most a very little worn at the edges.
Five or six miles from Sungnam, the road left the course of the ravine, and began rapidly to ascend the steep spur which bounded it on the left. At first we followed a fissure in the clay conglomerate, which still had a thickness of nearly two hundred feet. Above, the ridge was rocky and very steep. When we had attained a sufficient height to overlook the valley by which we had ascended from Sungnam, I was able to estimate better than while in the ravine, the extent of the clay deposit. It was now seen to occupy both sides of the valley, and to be pretty equally diffused throughout, but certainly thicker on the left or eastern side,—in the upper part at least, for low down, just behind Sungnam, it capped a round sloping hill of considerable elevation to the right of the little streamlet and of the road. The valley did not narrow at the lower extremity, where it debouched into that of the Ruskalan, so much as to give any reason for supposing that it could have been closed by a barrier, so as to form a lake. Indeed, the absolute elevation of the conglomerate was so great at the upper end of the valley, that it would be necessary to suppose a barrier several thousand feet above the bed of the Ruskalan to produce such an effect. The greater thickness of the conglomerate in the upper part of the ravine, and the almost complete angularity of the fragments, were equally opposed to such a view. Nor was I able to form any probable conjecture as to the mode in which these accumulations had been formed.
ROCKS OF HANGARANG.
August, 1847.
In the earlier part of the day's journey, the rock, where exposed, was invariably clay-slate, not different in appearance from that which, commencing at Lipa, had been observed on every part of the Runang ridge. It dipped generally at a high angle, but was often much contorted. In the upper part of the ravine, thick beds of a hard cherty quartz rock alternated with the slate; and in the course of the last steep ascent, at an elevation of about 13,500 feet, the first limestone was observed. It was of a dark blue colour, very hard, coarsely stratified, and much veined with white calcareous spar. It seemed to dip at a high angle towards the north-east.
The ridge by which we ascended was quite bare of trees and exceedingly barren, producing very little vegetation of any sort, and no novelty, till we had almost attained an elevation of 14,000 feet. We then observed bushes of a species of Caragana (C. versicolor), the Dama of the Tibetans, a very curious stunted shrub, which is very extensively distributed at elevations which no other woody plants attain, and which, therefore, is much prized and extensively used as fuel. I had not met with it before, nor does it appear to extend at all into the wooded region of the Himalaya. We encamped on a flat piece of ground at 14,000 feet. Notwithstanding the elevation, the heat of the sun was very great during the day, but the evening and night were extremely cold.
HANGARANG PASS.
August, 1847.
Early next morning a short steep ascent of about 800 feet brought us to the top of the pass, which has an elevation of 14,800 feet above the sea. The Dama, in green patches from two to four feet in diameter, was abundant till near the summit. The pass occupies a hollow in the ridge, which rises considerably on both sides. To the north-west, on the northern exposure, there was at a short distance one small patch of snow, from which the pass and surrounding mountains were otherwise quite free. No remarkable difficulty of breathing was experienced by any of the party, except immediately after any exertion. The ascent was latterly so steep, that it was necessary to stop frequently to take breath, and the pulse was found to be very considerably accelerated when counted immediately after walking. There was, however, a great difference according to the individual; in one case it rose as high as 136; but a few minutes' rest restored it nearly to the usual standard.
At the crest of the pass, the rock was a hard bluish-grey limestone, traversed in every direction by numerous crystalline veins. I ascended the hill to the south-east, to an elevation of nearly 16,000 feet, which was within a few hundred feet of the summit. At that height it was composed of a mass of loose fragments of black slate, perfectly moveable, and so steep, that it was difficult to progress in an upward direction. Vegetation had almost disappeared; more, however, from the moveable shingly soil than from the elevation attained, for wherever a solid rock peeped out, straggling plants still lingered; the rhubarb, Biebersteinia, a minute saxifrage, and a yellow lichen, were the species which attained the greatest altitude.