Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/288



This fossil seems to have been first taken notice of under the name of Wurflicher (cubic) Feldspath by Karsten, who took his description from specimens in the Leskean cabinet now in Dublin (No. 907 b, &c.); and from a comparison of these with the specimens from Douce, the identity of Karsten's fossil, with Andalusite is ascertained. I have not found however, that his claim to the first detection of it has been mentioned by subsequent writers: although his opinion with respect to its affinity to felspar, accords with that which Haüy is disposed to adopt. Tableau comparatif &c. p. 217.

To this species is also to be referred a mineral which occurs in great abundance at Killiney in the County of Dublin, first observed there by Dr. Blake, and for some time considered as belonging to a non-descript species. It is most remarkable on the shore at the southern extremity of the cliff under the obelisk hill, where it appears thickly on the surface of beds of mica slate; and it seems to abound also imbedded in the substance of that rock, although less distinctly visible until it has been exposed to decomposition, being less affected by exposure than the rock in which it is contained

The Andalusite, when thus brought to view, appears generally in slender prismatic crystalline pieces rounded. at the angles, seldom sharp, promiscuously aggregated, sometimes in a stellular form, and of a greyish-black colour, remarkably contrasted with the lustre and light colour of the micaceous substance in which they appear. But in fresher pieces, the form, colour, cleavage, and other characters of this mineral are distinct; and I have observed an approach to the peculiar appearances which it presents at this place, in some Spanish, specimens, where the crystalline shoots had assumed a scapiform arrangement.