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Updated: May 4, 2025
A somewhat analogous interpretation is applicable to many other cases, where clay, sand, or angular detritus, alternate with ores and vein-stones.
Such as are purely chemical may be formed on a very steep slope, or may even incrust the vertical walls of a fissure, and be of equal thickness throughout; but such deposits are of small extent, and for the most part confined to vein-stones. It is chiefly in the case of calcareous rocks that solidification takes place at the time of deposition.
Another convulsion then burst open the rocks along the old line of fracture, and the first set of deposits were cracked and often shattered, so that the new rent was filled, not only with angular fragments of the adjoining rocks, but with pieces of the older vein-stones. Polished and striated surfaces on the sides or in the contents of the vein also attest the reality of these movements.
It is moreover acknowledged that even those mineral and thermal springs which, in the present state of the globe, are far from volcanoes, are nevertheless observed to burst out along great lines of upheaval and dislocation of rocks. Many of these bodies occur as vein-stones; such as silex, carbonate of lime, sulphur, fluor-spar, sulphate of barytes, magnesia, oxide of iron, and others.
Not that the original fissure is narrower where the greenstone occurs, but because more of the space is there filled with vein-stones, and the waters at such points have not parted so freely with their metallic contents. "Lodes in Cornwall," says Mr.
For another reason, the end of the universe seemed near; such cities as had been forgotten by Attila were decimated by famine and plague. The Latin language in its turn, seemed to sink under the world's ruins. Years hastened on. The Barbarian idioms began to be modulated, to leave their vein-stones and form real languages.
Gold has now been detected in almost every kind of rock, in slate, quartzite, sandstone, limestone, granite, and serpentine, both in veins and in the rocks themselves at short distances from the veins. In Australia it has been worked successfully not only in alluvium, but in vein-stones in the native rock, generally consisting of Silurian shales and slates. Mr.
Occasionally the metallic ores are disseminated in detached masses among the vein-stones. The various changes here represented are not ideal, but are exhibited in a section obtained in working an old Cornish mine, long since abandoned, in the parish of Redruth, called Huel Peever, and described both by Mr. Williams and Mr. Carne.
The quarrying of quartz rock differs little from the quarrying of other metalliferous vein-stones. The lode descends steeply, and the excavation must follow its course. Sometimes the quartz is so soft that it may easily be loosened with the pick. The harder rock is blasted. Soft quartz is that which is penetrated by numerous cavities, though the lumps between the cavities may be very hard.
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