Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/415

 depth. This is partly to be ascribed to the water being saturated with salt; but, during the rainy season, the stream is much augmented, and thus cannot be supposed so highly charged with saline matter. Notwithstanding this, neither the solvent nor mechanical effects of the spring seem to have much effect on the fossil salt of Cardona. The waters of this spring flow into the Cardonero, leaving in the valley a thick scaly crust of salt, resembling the ice formed around our brooks in similar situations. During the rainy season, it is asserted that the stream carries down such quantities of salt into the Cardonero as to kill the fish in that river. This assertion rests upon the authority of Bowles, an able naturalist; but he undoubtedly was led into error when he asserted, that the waters of the Cardonero at some leagues below the mines yield no trace of salt: from which he inferred, that salt may, by motion, be converted into earthy matter. At Manresa, which is about twenty miles below Cardona, I tested the water of the Cardonero by nitrate of silver, which indicated the presence of an unusually large portion of muriate of soda. The taste of the brine spring at Cardona is intensely saline; and the hand immersed in it, on being exposed to the air, is instantly covered with a film of salt. The salt rock near its source is most elegantly veined with delicate waved delineations of an ochre yellow colour.

The clay which covers the bed of salt at Cardona and forms the sides of the valley, exactly resembles the clay found in the salt district of Cheshire, having when dry some resemblance to shale but becoming plastic when moistened. It is remarkably pure, and free from intermixture except of salt, large masses of which are occasionally imbedded in it.