Du Loup, one of its principal branches from the east. Assays from some of these veins show a percentage of silver ranging from $30 to over $400 per ton. The veins are of good size, but the largest deposit, that of Risborough and Marlow, is at present accessible with difficulty. This will be shortly overcome by the proposed extension of the Quebec Central Railway, which is to cross this area. Then these properties should become very valuable.

Of the iron-ores it need only be said that deposits occur at various points, some of which are of great purity and excellence. The great drawback, at present, to their successful working is the lack of suitable fuel for smelting, wood for charcoal being generally too scarce in the immediate vicinity, while the geological formations in Quebec and Ontario are such as to render the chances of finding coal in either province an impossibility. Should the problem of cheap transportation of coal, either from the mines of Nova Scotia or from those of the United States, to some central point, such as Montreal or Sherbrooke, ever be solved, it is confidently anticipated that these ores will form no inconsiderable factor in the mineral wealth of eastern Quebec.

The deposit of antimony near Garthby has been known for many years, and beautiful specimens can be obtained there, but the lack of a market, in view of the occurrence of large veins of the mineral in Nova Scotia and New Brunswick, and the lack of facilities for extraction on the spot, have hitherto interfered with its successful development. This, also, is one of the problems that should be solved in the near future.

It will be seen from this sketch of some of the leading minerals in this portion of the Dominion, that the chances for the profitable investment of capital in several important lines are not few. Improved methods of mining, a more extended market, and, in the case of the gold, greater security of title to those desiring to invest with a view to scientific mining operations will do much to improve them. The great value of these several industries is only now beginning to be understood, and it can be safely predicted that before many years the mining industries of this section will take a much more prominent position than they have ever yet enjoyed, and will be regarded with increasing favor as a field for profitable investment by capitalists both at home and abroad.

DISCUSSION.

R. G. LECKIE, Sherbrooke, P. Q.: Dr. Ells has referred to the occurrence of gold in the Eastern Townships. Through the courtesy

of Messrs. Ives and Pope I am in a position to submit to the Institute samples of the gold gathered during the last year at Ditton, when it was washed from the bed of a small stream, within the width of 100 feet. The rocks of that portion of the country have been described by Sir William Logan as Upper Silurian, but Dr. Ells's more recent observations class them as Cambrian, perhaps Lower Cambrian. They are intersected by veins of quartz, varying in width from 6 inches to 1 foot. At a distance of two miles from the locality where the gold exhibited has been collected a bunch of quartz was struck, from which about $600 worth of gold was extracted simply by hammering, even without a mortar. No further explorations have been made. What gold has been obtained has been collected by the crudest means, the farmers washing it out in the most primitive way, after their harvesting has been finished. Within a year it is probable that a systematic effort will be made to trace the source of the precious metal.

NOTES ON THE GEOLOGY OF THE DEKAAP GOLD-FIELDS IN THE TRANSVAAL.

BY W. H. FURLONGE, JOHANNESBURG, S. A. R.

(Washington Meeting, February, 1890.)

WHILE fulfilling professional engagements, my travels over this portion of the Transvaal have been quite extensive-always on horseback however, so that anything like a thorough investigation of the ground passed over has been necessarily impossible; still, the more minute examination of certain small areas, coupled with general observations, has enabled me to form some idea as to the prominent geological features of the country as a whole.

Anything like a complete or comprehensive description is indeed out of the question, as there are no proper maps of the country and the facilities for observation are limited. A large plateau, called the "High Veldt," stretches from east to west across the Transvaal. It is generally level, or gently rolling, and has an average elevation of 6000 feet above the sea; it is destitute of timber, and in fact greatly resembles the western prairies of North America. Rock-outcrops are not common in it. It terminates very abruptly to the east and northeast, the descent of 2000 or 3000 feet into the mountainous country that occupies its borders being made in a

very short distance. These mountains extend in an easterly direction for a distance of 40 miles, when they again terminate, very abruptly, in an apparently flat region composed of marshes and sandy plains, sloping gently, but regularly, to the shores of the Indian Ocean, a distance of about 100 miles.

The gold-fields of this section of the country lie among these mountains, whose summits, however, rarely attain the elevation of the "High Veldt," while the valleys between them are from 2500 to 3000 feet above the sea.

The accompanying map is the best obtainable; and, though it is far from accurate, it will give an idea of the geology and topography of the district.

The gold-fields are provisionally sub-divided by the Government; but for the purposes of this paper I propose to ignore both political and geographical boundaries, and will therefore include in my description all the country from the eastern edge of the High Veldt to the coast plains, and, from north to south, the region from the northernmost edge of the DeKaap Valley, to nearly the center of Zwazieland.

In general, it may be said that these mountain ranges run in a northeast and southwest direction, though they vary in many instances considerably from that course. As a rule they form fairly continuous chains, though isolated peaks are not uncommon. They usually present a serrated appearance, and are essentially similar, though in miniature, to the Sierra Nevada mountains of California; differing from them in one particular, namely, that their slopes are steeper. This I account for by the absence of frost in this region. Rock-disintegration, and the consequent formation of a talus, is comparatively slow work; and what little rock has been loosened is washed away by the torrents of rain so prevalent during the wet season. Only an eye-witness can form an idea of the violence of these storms, or of the enormous amounts of material removed to lower levels during one of them. It is entirely owing to this cause that there is but little "surface" or "wash " throughout this part of the country. At such times the rivers, which have, perhaps, an average fall of 25 feet per mile, become raging torrents; and when the floods subside, it is found that the channels are pretty well cleaned out to bed-rock. As a consequence there are no deposits of gravel, as we find them in other parts of the world, and little or no chance for river, and absolutely none for hydraulic, alluvial mining. None of the rivers show the evidences of great an

tiquity; there are no cañons or gorges cut away, or, if they exist, they are insignificant; no terraces, no well marked channels, and the approach to the river-beds is in almost all cases down a very easy gradient. Nor, so far as I can ascertain, have any ancient river-beds been discovered in the country.

I have diligently searched for, but failed to find, evidences of glacial action, phenomena with which I happen to be very familiar from my residence in the Lake Superior district and the country north of it.

Here, as in other gold-mining countries, are found large granitic areas and belts, flanked by schistose and shaly rocks, which contain the auriferous quartz-veins.

The granite, occupying as it does such an extensive area, may be described first. Its prevailing color is white, or rather lightred. The greater part of it is true granite, containing, however, but little mica, which, so far as I have observed, is invariably muscovite. The quartz seemingly always predominates, and the feldspar, though principally light-red (occasionally white) orthoclase, is, as a rule, accompanied by a large proportion of plagioclase (albite?). Very generally there occurs in this granite a little darkgreen hornblende, and occasionally the rock passes gradually into, first, syenitic granite, and then true syenite.

Con

These granitic rocks are often decomposed to a considerable depth over large areas. I wish particularly to draw attention to the following facts, which may have some bearing on the theory of rockdecay, as advanced by Professor T. Sterry Hunt. The granite here is decomposed only, either in the natural drainage-channels, i.e., below "water-level," or in places where the surface- and rain-waters can at least remain in contact with it for a considerable time. sequently it is only in flat places that the granite is found to be decomposed; while on the slopes of the hills bordering these areas, and to which this decayed granite can be traced in unbroken continuity, the rock has merely the ordinary weathered appearance. is quite solid under the hammer; and, furthermore, instances are frequent where boulders, evidently in situ, microscopically undecomposed, rest on the same material, which, being constantly wet, is in a decayed state. In other words, though subaerial decay goes on here as elsewhere, but not so rapidly, the almost universal decomposition of these rocks must apparently be mainly, if not entirely, attributed to the agency of meteoric waters remaining for some length of time in contact with them.

It

The orthoclase is usually transformed into an arenaceous clay, while the triclinic feldspars are more or less perfectly kaolinized, and sometimes crumble under the fingers. The quartz, of course, remains, though it generally soon disintegrates into a fine sand.

This decayed granite often covers immense tracts. The town of Barberton is built on the eastern edge of one of them, which is at least 16 by 18 miles in extent. A striking feature throughout the large areas, is what are locally known as "dongas." They are merely water-washes in the decomposed rock, are often of great extent and depth (the latter reaching 200 feet), and sometimes present the most fantastic and picturesque appearances. The accompanying photograph was taken of one of the more striking. I merely state, in explanation, that the rock seen is entirely decayed granite, which is on a "flat," and in a natural drainage-channel ; while the hills in the background are composed of the same rock, but in a normal or solid condition. The fragments that have rolled down the hill on to the "flat," and which have been subjected only to the ordinary atmospheric action, are also undecayed.

This description of rock-decomposition not only applies to granite, but to all feldspathic and apparently eruptive rocks. With them, the decay is even more marked, as they contain no quartz, and, though perfectly solid as blocks on the surface, the underlying mass can generally be dug out with a spade to depths ranging from 50 to 100 feet, or perhaps more. The decayed granite, on the contrary, though it will sometimes crumble in the hand, yields only to the pick, as a rule. I have also observed one or two instances of decayed hornblendic schists, though, so far as I know, these are rare.

In describing the remaining rocks of the district, it is convenient to have a starting point; so I take the large basin on the southeastern edge of which the town of Barberton is built.

This basin, which I have previously stated to be entirely floored by decayed granite, is surrounded on all sides by mountains 1500 to 3000 feet in height. This last-named elevation is only attained on the western side, where an abrupt ascent to the flat-lying rocks of the High Veldt, which rest immediately on the granite, takes us into an entirely distinct geological horizon. Surrounding this roughly circular basin on the other three sides, are the rocks amongst which the auriferous deposits of the DeKaap fields lie.

All these rocks are highly inclined. Their strike is in general tangential to the edge of the granite basin, and they dip, in all cases, away from it, at angles varying from 60° to 90°. It would appear

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