212 Mineralogical Notices. 



glass. On analysis it afforded Prof. Shepard, Silica 34-75j pro- 

 toxyd of iron 31-25, alumina 8-55, water 547, making a loss of 

 nearly 20 p. c, a portion of which he attributes to the alkalies. 

 6-146 gramme was used in the analysis. Neither lime nor mag- 

 nesia were detected. The name is from Corundum and (ft'kog^ 



fi 



[This mineral, as observed by the writer, is usually thin foH- 



ated or micaceous. It closely resembles chloritoid in appear- 

 ance, which, as stated by J. Lawrence Smith, who analyzed a 

 specimen, occurs frequently with the Corundum of Asia Minor; 

 but it divides into much thinner laminae than is usual in that 

 species and is less brittle. The angles are nearly those of com- 

 mon mica.] 



2. Desa'ibed Species. 



On some Canadian Minerals^ by T. S. Hunt, (Phil. Mag., 

 [4], i, 322.) 1. Perlhite^ of Thomson. — This feldspathic min- 

 eral is from Bathurst, and forms part of aeurite rock, being some- 

 times in large cleavable masses. Form apparently monoclinic. 

 H. = 6. G.=2-576-2-579; a darker colored fragment 2-583. Lus- 

 tre vitreous, inclining to pearly; color a light flesh red, in alter- 

 nating bands, with reddish or pinchbeck brown, the bands half a 

 line or a line wide, coincident with one of the planes T ; the 

 darker bands on the cleavage surface T give a golden reflexion 

 when viewed perpendicularly, like aventurine feldspar. Analysis 

 by Mr. Hunt. 



Si S:l Pe Ca' ]&^ fe S'a 



6644 18-35 1-00 0-67 24 6*37 5-56 ign. ■40=9903 

 66-50 19-25 0-56 0*24 6'18 6-56 " •44=^98-73 



The composition is that of orthoclase, to which species, as he 

 observes, the mineral had been referred by Shepard, Dana and 

 himself, 



2. Peristerite^ Thomson. — The specimens furnished Mr. Hunt 

 by Dr. Wilson, as duplicates of those sent to Dr. Thomson, were 

 a feldspar containing disseminated quartz grains; and others from 

 the locality were fine cleavable masses often free from the quartz. 



Form triclinic, 



perfect 



P and M, less distinct with T, a fine play of colors on P, as in 

 labradorite, a delicate cerulean blue prevailing which occasionally 

 passes into light green and yellow. H. = 6. G.= 2 625-2 627'. 

 Composition according to Mr; Hunt: 



§i *1 Pe Na S: <5a Mg 



L 66-80 21-80 O'SO 7-00 0-58 2-52 0*20 ign. 0-60=:99-80 

 n. 67-25 , 2-03 ** 0-66 



whence the mineral is alhite. 



3. Bytownite- 



Hoi 



and was taken from a specimen pronounced by Dr, Thomson to 



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