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Updated: June 26, 2025
Hittell says: "The Mother Lode is one of the most extraordinary metalliferous veins in the world. Gold-bearing lodes usually range only five or six miles, but this can be traced for more than sixty. The rock is a hard and white quartz, rich in very fine particles of gold, and the vein varies in width from a foot to thirty feet.
Independently of this local metamorphic action, all the strata undoubtedly display an indurated and altered character; and all the rocks of this range the lavas, the alternating sediments, the intrusive granite and porphyries, and the underlying clay- slate are intersected by metalliferous veins.
Granite Veins in Glen Tilt, Cape of Good Hope, and Cornwall. Metalliferous Veins in Strata near their Junction with Granite. Quartz Veins. Exposure of Plutonic Rocks at the surface due to Denudation. The Plutonic rocks may be treated of next in order, as they are most nearly allied to the volcanic class already considered.
These facts appear to me opposed to the theory, that rock-salt is due to the sinking of water, charged with salt, in mediterranean spaces of the ocean. It is worthy of notice, that the foliation of the gneiss and mica-slate, where such rocks occur, certainly tend to run like the metalliferous veins, though often irregularly, in a direction a little westward of north.
Further up the valley, here running nearly north and south, the gypseous formation is prolonged for some distance; but the stratification is unintelligible, the whole being broken up by faults, dikes, and metalliferous veins.
The preceding chapter dealt more especially with prospecting as carried on in alluvial fields. I shall now treat of preliminary mining on lodes or "reefs." As has already been stated, the likeliest localities for the occurrence of metalliferous deposits are at or near the junction of the older sedimentary formations with the igneous or intrusive rocks, such as granites, diorites, etc.
Twenty years ago very few mining shafts in the world had reached a depth of 2,000 feet. The very deepest at that time was in a metalliferous mine in Hanover, which had been carried down 2,900 feet; but this was probably not a single perpendicular shaft. Two vertical shafts near Gilly, in Belgium, are sunk to the depth of 2,847 feet.
In this region we found nothing extraordinary except vast forests and some metalliferous hills, as we infer from seeing that many of the people wore copper ear-rings. Departing from thence, we kept along the coast, steering north-east, and found the country more pleasant and open, free from woods, and distant in the interior we saw lofty mountains, but none which extended to the shore.
Then followed a conversation with Haji Wali, whom age he was 77 "had only made a little fatter and a little greedier," and the specious old trickster promised to accompany the expedition. As usual Burton began with a preliminary canter, visiting Moilah, Aynunah Bay, Makna and Jebel Hassani, where he sketched, made plans, and collected metalliferous specimens.
But as in Nature's laboratory the processes, if certain, are slow, this theory may be difficult to prove. Why the junction of lodes is often found to be more richly metalliferous than neighbouring parts is probably because there the depositing reagents met. This theory is well put by Mr. S. Herbert Cox, late of Sydney, in his useful book, "Mines and Minerals."
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