202 



stove for tlie last two years, and altliougli it became slightly discolored 

 it nevertheless compares favorably with some grades of the commercial 

 article. At Cbitty's mine in Wakefield, great quantities of this mineral 

 were met with, capable of supplying very large plates, although occa- 

 sionally marred by lateral joints. 



What this mineral lacks in a commercial point of view is more 

 than counterbalanced by the magnificent prisms available to the scien- 

 tific world. For symmetry of form the crystals lining the walls of 

 fissures, or enclosed in limestone, are not livalled in the Dominion. 



At Moore's mine, in Wakefield, prisms over a foot in diameter 

 with lateral planes varying from an inch to a foot or more, stand out 

 in relief on the dissolved surfaces of the limestone. Thin plates of this 

 mineral are remarkable for showing in a strong degree the asterism or 

 I'adiating star when viewed through a transparent plate of it. This is 

 due, according to G. Rose, to intersecting minute crystals of biotite, 

 but considered by Tschermak to be .some undetermined substance. 

 More recent investigations have put forth rutile as the inclusion. 

 This peculiarity does not extend to all our n.icas alike, as non-asteriated 

 varieties ai'e frequently associated with the asteriated. Neither is it 

 confined to any particular color, as the pearly white and the black both 

 exhibit these optical characters. Prisms of the black variety often 

 exhibit lateral cleavages, which are easily obtained, breaking up into 

 rhombic forms. On lot 7, range 1, in the same township, a pearly 

 Avhite sometimes tinged with a copper red color occurs in a bed of lime- 

 stone often holding concretionary inclusions of calcite. These ci-ystals, 

 which are sometimes twinned, are peculiarly characterized by a pho.s- 

 phore^cent light that glows momentarily when the plates are suddenly 

 })arted. Large aggregates of these crystals are sometimes met with 

 wheie one-half the prisms, laterally, are transformed in a slightly 

 micaceous steatitic rock, the unaltered portion having thin films of 

 carbonate of lime interpolated between the lamin?e. 



Oligoclase. — A mineral occaring in veins in a gray pyroxene rock 

 on lot 16, range 12, of Hull, has been referred by Mr. Hoffmann to 

 oligoclase. It is often beautifully crystallized, of a slightly translucent 

 white color, weathering to an opaque milky white. 



Aibite. — This mineral is mentioned by Dr. Harrington as occur- 

 ling at several i)laces in Templeton. No locality being cited, it is 



