tion has removed all traces of the vent and left a solid projecting mass, with a shelving top. It is precipitous on every side, and all my endeavours to climb it were useless, for although, in one place, I reached within about 100 feet of the top, I could not get higher without a ladder. The Burmese said that formerly it could be scaled, but some rocks had since fallen down, and now they could only get up by means of bamboos. As I had so little time, I would not waste it by waiting to make a ladder, but went on to examine the beds forming the scarp already referred to as surrounding the mountain. The results, which I only made out clearly on the following morning on my way down from the mountain, when returning to Pagán, were the following. The great terrace consists of sands and sandy clays generally horizontal, but occasionally disturbed, probably by dykes, which abound in the neighbourhood of Toung-galá and in some other places. On the top is a cap, varying in thickness, of ash beds and lava flows. This cap is beautifully seen on some small outliers detached from the terrace and called Toung-thong-loon (the three hills) which lie about three miles west of the village of Puppá, and consist of sand with a covering thirty or forty feet thick of volcanic ashes, upon which rests lava of about the same thickness. All of these lavas are of the same character as the rock of Toung-galá, but less distinctly crystallized.* From opposite the most southerly of the Toung-thong-loon, a valley excavated by a stream, the head-waters of which supply the village of Puppá with water, extends for some distance into the hill, and its precipitous sides, where not concealed by tatees, shew the fine section given beneath. The thickness assigned to each bed is only approximate, as the sides of the valley were, in most places, too nearly vertical to be accessible. 1. Lava of variable thickness capping the whole. 2. Soft sands and sandy clays, yellow and greenish with black specks; micaceous, about ......... 80 feet. * I am not quite certain whether the mineral I have called augite may not be hornblend. A few detached crystals which I found among the ash beds near the top of the mountain had the crystalline form of the latter mineral. The mass of the lava is grey and somewhat resembles phonolite, but is beautifully marked by the black augite (or hornblend) crystals. It would be a beautiful stone for ornamental purposes. 3. White sandy bed abounding in fragments of on the South side of the valley; on the North 4. Volcanic ash containing quartz pebbles, thicker 5. Ferruginous gravel and sandy clay, containing 6. It contains pebbles in places. ...... Upwards of 100 seen. It is evident that the ash bed, No. 4, is of the same general age as the sands above and below, and that it was deposited in water is clear from its containing quartz pebbles. There can, therefore, be no doubt that it records an eruption of the mountain, perhaps with an east wind blowing, at the time when the lake or estuary, which then surrounded Puppá, was being gradually filled up by sandy deposits. There can be also little question as to the identity of the beds of the above section with the sands and conglomerates containing fossil wood and mammalian bones at Yénánkhyoung, Pagán, &c. Fragments of fossil wood evidently derived from these deposits are found about Puppá, and to complete the evidence, I found a piece, not rolled as such blocks are in the more recent gravels, in situ in the ash bed itself. The period during which Puppá was in action was therefore, in parts at least, not later than that of the deposition of beds containing remains of Elephas, Mastodon, Rhinoceros, Hippopotamus, and Ruminants. The geological age of these beds has, with some doubt, been considered to be Miocene, but from their general fauna, and especially from the abundance of bones of Bos and Cervus, a more recent date may, I think, with at least equal probability, be assigned to them. There can be no question but that the fires of Puppá have long been extinct; its thick coating of jungle and grass, and the existence upon it of species of plants and animals, which, for want of a suitable habitat, cannot exist in any neighbouring locality, and the evidence of the effects of subaerial denudation on its surface, render it certain that it must long have been in a condition for vegetation to flourish upon it, but it is scarcely possible, even in the dry climate of upper Burma, that a volcano of Miocene age should have retained its form so perfectly. It is more probably Pliocene. Its bulk is not great, and, from the absence of other vents in the neighbourhood, so far as is known, it is scarcely probable, that its volcanic activity can have extended over a lengthened geological period. I could not learn that there was the slightest tradition among the people as to its ever having been in action within the memory of man, a circumstance, on the grounds mentioned, extremely improbable. The occurrence, on the summit, of the common brakes, and doubtless of other plants of temperate regions, renders it probable that the close of the glacial period found its surface in a fit state to support vegetation. The discovery of a volcano of comparatively recent geological date in Burma is the more interesting from the circumstance that the long line of volcanoes which has been traced throughout the Eastern archipelago has hitherto appeared to end abruptly at Kyouk Phyú on the Arakan coast. The so-called mud volcanoes of Memboo have no connexion with true volcanic action, but igneous eruptions have been recorded at Kyouk Phyú and Chedúba.* Puppá is very little removed from the continuation of a line passing through Barren island and Ramri, and there is thus a possibility of the extension of the great eastern line of volcanic outbursts into the countries of Western China; probably, as at Puppá, in the form of extinct cones. I left Puppá on the 30th October, and reached Pagán the next day about mid-day, the road by which I returned being somewhat shorter than that by which I went to the mountain. *There is a great peak standing out prominently from the west or Arakan side of the Yoma, a little north of west from Rainri. I have no idea of what its geological formation is, but it does not look like a volcano. Still it may have been one. |