The picture is not enticing,—but this is, nevertheless, the true arida nutrix of the splendid masses before us. The zone of metamorphic rocks which lines this inhospitable coast varies in width from six or eight miles at its eastern extremity to forty or fifty at its widest points,—presenting in its northern boundary only a rude parallelism with its southern margin,—and comprising, over about six thousand square miles of surface, the general outline of what may, geologically speaking, be called the Gold-Region of Nova Scotia.
It will be most interesting hereafter to mark the gradual changes already beginning to take place in this rich, but limited district. It is destined throughout, we may be sure, to very thorough and systematic exploration. For, although it is true that gold is not to be found in all parts of it, still it is not unreasonable to search for the precious metal throughout this whole region, wherever the occurrence of true quartz-veins—the almost sole matrix of the gold—is shown by boulders on the surface. Back from the coast-line, a large part of the district named is now little better than an unexplored wilderness; and the fact that the remarkable discoveries which have been made are in a majority of cases almost on the sea-shore, and where the country is open and the search easy, by no means diminishes the probabilities that continued exploration in the less frequented parts of the district will be rewarded with new discoveries as important as any which have yet been made.
The earliest discovery of gold in the Province, yet made known to the public, occurred during the summer of 1860, at a spot about twelve miles north from the head of Tangier Harbor, on the northeast branch of the Tangier River,—shown on McKinley's excellent map of Nova Scotia as about fifty-eight miles east from Halifax. Subsequent discoveries at Wine Harbor, Sherbrooke, Ovens, Oldham, Waverley, Hammond's Plains, and at Lake Loon,—a small lake only five miles distant from Halifax,—have fully determined the auriferous character of particular and defined localities throughout the district already described, and abundantly justify the early opinion of Lord Mulgrave, that "there is now little or no doubt that this Colony will soon rank as one of the gold-producing countries of the world."
As a specimen of one of the most interesting mineral veins of this region, it may answer to select the Montague lode at Lake Loon for a specific description. The course of this vein is E. 10° N., that being the strike of the rocks by the compass in that particular district. It has been traced by surface-digging a long distance,—not less, probably, than half a mile. At one point on this line there is a shift or fault in the rocks which has heaved the most productive portion of the vein about thirty-five feet to the north; but for the rest of the distance, so far as yet open, the whole lead remains true and undisturbed.
Its dip, with the rocks around it, is almost vertical,—say from 85° to 80° south. The vein is contained between walls of slate on both sides, and is a double or composite vein, being formed, 1st, of the main leader; 2d, of a smaller vein on the other side, with a thin slate partition-wall between the two; and, 3d, of a strongly mineralized slate foot-wall, which is in itself really a most valuable portion of the ore-channel.
The quartz which composes these interposed sheets, thus separated, yet combined, is crystallized throughout, and highly mineralized,—belonging, in fact, to the first class of quartz lodes recognized in all the general descriptions of the veins of this region. The associated minerals are, here, cuprite or yellow copper, green malachite or carbonate of copper, mispickel or arsenical pyrites, zinc blende, sesquioxyde of iron, rich in gold, and also frequent "sights" or visible masses of gold itself. The gold is also often visible to the naked eye in all the associated minerals, and particularly in the mispickel and blende.
The main quartz vein of this interesting lead varies from three to ten inches in thickness at different points on the surface-level, but is reported as increasing to twenty inches thick at the bottom of the shaft, already carried down to a depth of forty feet. This very considerable variation in thickness will be found to be owing to the folds or plications of the vein, to which we shall hereafter make more particular allusion.
The minerals associated with the quartz in this vein, especially the cuprite and mispickel, are found most abundantly upon the foot-wall side, or underside of the quartz itself. The smaller accompanying vein before alluded to appears to be but a repetition of the larger one in all its essential characteristics, and is believed by the scientific examiners to be fully as well charged with gold. That this is likely to come up to a very remarkable standard of productiveness, perhaps more so than any known vein in the world, is to be inferred from the official statement in the "Royal Gazette" of Wednesday, January 20, 1864, published by authority, at the Chief Gold-Commissioner's office in Halifax, in which the average yield of the Montague vein for the month of October, 1863, is given as 3 oz. 3 dwt. 4 gr., for November as 3 oz. 10 dwt. 13 gr., and for December as 5 oz. 9 dwt. 8 gr., to the ton of quartz crushed during those months respectively. Nor is the quartz of this vein the only trustworthy source of yield. The underlying slate is filled with bunches of mispickel, not distributed in a sheet, or in any particular order, so far as yet observed, but developed throughout the slate, and varying in size from that of small nuts to many pounds in weight, masses of over fifty pounds having been frequently taken out. This peculiar mineral has always proved highly auriferous in this locality, and a careful search will rarely fail to detect "sights" of the precious metal imbedded in its folds, or lying hidden between its crystalline plates.
Nor is the surrounding mass of slate in which this vein is inclosed without abundant evidences of a highly auriferous character. Scales of gold are everywhere to be seen between its laminæ, and, when removed and subjected to the processes of "dressing," there can be little doubt of its also yielding a very handsome return. In fact, the entire mass of material which is known to be auriferous is not less than twelve to fifteen inches at the surface, and will doubtless be found, as all experience and analogy in the district have hitherto shown to be the case, to increase very considerably with the increased depth to which the shafts will soon be carried. No difficulties whatever are apprehended here in going to a very considerable depth, as the slate is not hard, and easily permits the miner in his progress to bear in upon it without drilling upon the closer and more tenacious quartz.
The open cut, made by the original owners of the Montague property, and by which the veins have been in some degree exposed, absurd and culpable as it is as a mode of mining, has yet served a good purpose in showing in a very distinct manner the structure of these veins,—a structure which is found to be on the whole very general in the Province. The quartz is not found, as might naturally be supposed from its position among sedimentary rocks, lying in anything like a plain, even sheet of equal thickness. On the contrary, it is seen to be marked by folds or plications, occurring at tolerably regular intervals, and crossing the vein at an angle of 40° or 45° to the west. Similar folds may be produced in a sheet which is hung on a line and then drawn at one of the lower corners. The cross-section of the vein is thus made to resemble somewhat the appearance of a chain of long links, the rolls or swells alternating with plain spaces through its whole extent. Perhaps a better comparison is that of ripples or gentle waves, as seen following each other on the ebbtide in a still time, on the beach.