Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/170

 158 be called; on entering them with a torch we discover vast chambers or excavations placed one above mother, very much resembling the different stories of a house, with a common entrance.

The mine worked at Rammelsberg, and which is of so great an extent, does not appear to be a vein, but an immense mass of ore deposited in that place in the same manner as mountains are formed. Werner is also of opinion that the vein (spitaler hauptang) at Schemnitz, mentioned by Born, as well as two others of equally great thickness, worked in the same place, are rather banks of ore than true veins, judging from the uniformity of their direction and inclination, from their nearly horizontal position, and from what is said of their thickness.

Veins have originally been fissures in mountains, and intersect the strata or beds of which the mountain is composed. These fissures have been filled from above by substances differing more or less from those of which the mass of the mountain that they intersect is composed, and those substances have been precipitated from a liquid solution.

Werner has brought forward so many facts in support of these two fundamental positions, that his theory scarcely receives a greater degree of stability by any of the farther proofs which are daily discovered.

Two particular cases have come to my knowledge, which I shall, notwithstanding, briefly mention. The one proving that veins have