Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/293

 same situation may be seen thin beds of a compact pale green and transparent steatite, and irregular lumps of the same substance are frequently found dispersed about the beds.

It is rare to find distinct pieces of noble serpentine of any magnitude, but they are also met with, and of a transparency and greenness equal to that of the well known specimens from Iona.

Talc of various colours, white, lead-blue and green is likewise met with among the marble beds, but in small quantity: and asbestus, although it is seen here and there in considerable pieces, may also be considered rare. But it produces abundance of tremolite, and offers some interesting and uncommon varieties of that beautiful mineral.

Of these, the first is fibrous and very compact, having a slight purplish tinge, particularly when viewed according to the axis of its crystallization. It is imbedded in the rock, with which it is perfectly compacted, presenting on fracture a small stellated or a longer radiated appearance, and giving a peculiar character to the marble.

The next variety consists of a congeries of regular prismatic crystals, varying from a tenth to a sixth of an inch in diameter. These are seldom radiated, but most commonly form a dense mass of which the crystals are irregularly interwoven together, and sometimes curved. Thin beds of this are found between the marble beds, and in some cases the crystals have shot in cavities so is to present terminations, which, however formerly complete, have been spoiled by the action of the water on them.

It is well known to mineralogists that many substances when found in the earth are in a soft state, and only acquire induration when removed from their native beds. If we are to believe Patrin the same is true even of the beryl. It is so with the tremolite which I have now described, which is exceedingly soft and flexible when first up, but hardens after some days of desiccation. The asbestus taken