Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/427

 red felspar, in a fine grained combination with quartz and mica, is the common rock of the country, which however is never here found uncovered. It occurs only in detached blocks as well at the foot as at the highest top of the mountain, which is besides partially covered with a fine white sand to a considerable depth; with siliceous gravel and small blocks of amorphous garnet with specks of iron. Slaty quartz is also found in small fragments, but never forming a solid rock.

The above mentioned layers of iron-ore have in all the mines and all over the mountain a general direction from north—east to south-west, dipping about 45° to north-west. They very often stretch several hundred fathoms in length, and from two to three hundred in breadth, merely covered by a slight vegetation of mosses. If we except the red felspar, which at small distances runs parallel with the ore and sometimes crosses its layers, the whole forms almost a solid mass of iron, of a very considerable extent, and of an unknown depth. In those places where the ore is of a loose texture and either coarse or fine-grained, a large quantity can in an hours time be dug up by a spade. The more hard and compact magnetic ores break generally in rhombs, the angles of which are about 45°, or equal to the dipping of the layers,

The ores, of which I hope to give a more detailed account at another time, form the most complete series of iron in different degrees of oxidation, from the almost black magnetic ore to the light gray not the least magnetic., (eisenglanz, Werner, ) the true substance of which shews itself by its red colour when rubbed. The greatest number of ores forming this series, may probably be considered as a more or less intimate though merely mechanical combination, between the two varieties of iron in its minimum and maximum of oxidation. The variety mentioned by Count de