Dr. How on the Mineralogy of Nova Scotia. 337 



Since the iron exists in small proportion as peroxide, there is 

 a close general accordance between the numbers found, especi- 

 ally in the third analysis, and those given for Wichtyne by Lau- 

 rent (Dana's 'Mineralogy/ 4th edit. p. 177), viz. : — 



Silica 56-3 



Alumina 13*3 



Peroxide of iron .... 4*0 

 Protoxide of iron . . . 13*3 

 Lime ...'... 6*0 



Magnesia 30 



Potash and a little soda . 3*5 



99-4 

 The physical characters of Wichtyne, as stated by Laurent, 

 agree upon the whole tolerably well with those given above; 

 they are — specific gravity 3*03, hardness sufficient to scratch 

 glass, colour black, lustre dull. There is therefore little doubt 

 that the Nova Scotian mineral now described is rightly referred 

 to the species Wichtyne, which, taking all its characters and its 

 composition into consideration, it resembles more closely than it 

 does any of the allied minerals, glaucophane, violan, Sordawalite, 

 and tachylite. The whole group is of extremely rare occurrence, 

 none of the members of it apparently being found at more than 

 one or two localities. The only locality given for Wichtyne is 

 Wichtis in Finland, whence Hausmann changes Laurent's de- 

 signation to Wichtisite, which seems preferable. The matrix of 

 the mineral at Cornwallis, N.S., is, as I found on examination 

 of small adherent portions, a soft yellowish mineral containing 

 peroxide of iron and carbonate of lime, the latter being appa- 

 rently most abundant ; it is possibly a limestone. 



Pencil-stone. — A mineral with this local designation is found 

 in a thin bed extending for a considerable distance through rocks ; 

 considered to be of the age of the Hudson-River group, about 

 Merigomish in the eastern part of the province. It is of an ash- 

 grey colour, a somewhat schistose structure and close texture, 

 adheres slightly to the tongue, and feels rather soapy on smooth 

 surfaces; it has a glimmering lustre, and is most readily cut 

 with a knife ; its hardness is 1'5, its powder and streak are grey- 

 ish white. From the circumstance of excellent soft but firm 

 pencils, much prized for writing on slates, being made from it, 

 it receives its local name. Analysis shows it to belong to the 

 clay-slate family ; it was at first taken for pyrophyllite, the com- 

 pact variety of which, used in the United States for making pen- 

 cils, it much resembles. It also in some respects agrees with 

 agalmatolite, with which the compact pyrophyllite had been con- 

 founded before Brush pointed out that they were really distinct 

 (Silliman's Journal, July 1858, p. 69). Its specific gravity is 

 Phil. Mag. S. 4. Vol. 33. No. 224. May 1867. Z 



