the specimens which I have described above. The last specimens I in point of structure which I shall notice, consist of radiated mesotype intermixed with crystals of hornblende, and producing a compound of an unusual appearance.
The specimens which I have now described are almost invariably colourless and transparent, or white, but occasionally they assume a brown tinge. One specimen occurred of a sea greed hue and of perfect transparency; but the flesh colour not uncommon in this mineral did not fall in my way, although found in the other members of this family which are seen here.
With respect to the exact locality of this substance, I have only found it at Talisker and at Dunvegan, although it is probable that it exists in many other parts of this very extensive island, which the labour of years would scarcely suffice to examine with the scrupulosity necessary for this purpose.
It was at Dunvegan that I observed a solitary crystal of ichthyophthalmite, nor did I succeed in discovering a second. It appears that laumonite has been also found in Sky: in the course of my researches I observed some minute specimens of it associated with stilbite, but scarcely worthy of notice, unless for this slender record of their habitat.
Prehnite, a mineral so nearly allied to the zeolites, is also found in Sky, but it is far from common, while the specimens are at the same time of trifling magnitude. It occurs in the trap at Portree, and at other points along the eastern shore, as well as at Strathaird, in the trap veins which traverse the sandstone, as I have already mentioned. On the shores opposite to the point of Clachan in Raasa it is found in a rock, which, although not very common, occurs in different parts of the western islands. This rock is a compound of augite, glassy felspar, and common felspar, the
