«EOLOiQY OP THE VICIMITY OF DUfil^m. S^? 



knife, faintly translucent, their .celOu^ yeUowish*gtay. . ; 



••^Small ffft^ments before the blowpipe appear to §well a UttJe 



■-'from the separation of the folia on the tirst application «f 



, -the heat ; they become white, and give with «ome difficulty a 



solid white enamel. The specimens to which 1 have access 



• at present do not enable me to give any detail of it^e renniin- 



ing characters. 



The connection of this substance with the andalusite of 



; l>ouce is remarkable ; the latter often forming the nnclei^s 



of crystals externally of four sides, sometimes billing nearly 



< the whole of the interior ; but in other specimens forming 



little more than an axis, with rounded edges, and of iw^ga- 



lar form, from which the folia of the>inve$tiug jLAlcUH^e;^"]^ 



' stance appear to radiate. •• 



' The occurrence of indurated talc in crystals has hitherto 



'been very rare: it is not mentioned by Jameson ; and Bro- 



chant, though he quotes from Emmerling the rhomboidal 



prism as one of its forms, expresses doubt as to the correct- 



"■ ness o( the statement ; I therefore do not give thst name to 



- the crystals found at Douce, without some uncertainty. 



-^ 6. HoUowspar, Jameson. (Made, Haiiy). Very;drs- ^ollowspar. 



» tinct specimens of this mineral have been found by Mr. 



Davy, at Aghavanagh in the copnty of Wicklow ; and I have 



> observed it at Baltinglasg hill, within a few miles^fthat 



place. 1 may mention here, that from the appearances of 



many specimens found in the neighbourhood of Killinej, 



Mr* Stephens was inclined to suppose, that a connection 



existed between this singular species and andalusite. 



7. Pitchstone. This substance is found in a vein tfavers- Pitchstoae^ 

 ing granite, in the vicinity of Newry iu the county of XXown. 

 I am indebted to Mr. Jameson of Edinburgh fpr much of 

 the following descriptiori^^f its«xterna^l.chacactierft, as it ap- 

 pears there. 



Its colour is intermediate between mountain and leek 

 green. It is massive. Fracture small ajad not very perf-^^t 

 ■ conch oidal. .' - 



Internal lustre, resi no- vitreous and shining.. . It ejthibits 

 lamellar distinct concretions ; the plates are from one fourth 

 to one tenth of an inch in thipkqess, and arejarvher divisi- 

 ble into pieces of the rtvoroboidal form of ya;ip^sitngles. 



The 



