Apatite Bearing Rocks. 221 



Ui'i., W * I If 1L 



cut through by the former. The syenite in places changes 

 color and character to some extent when passing from the 

 main mass into smaller dykes or spurs, especially where 

 these latter traverse the crystalline limestone, in which 

 case it often becomes a greyish white . This aspect can be 

 well studied at Papineauville among other places. 



These intrusions do not, however, carry apatite, at least 

 in any observed case, though they often contain fine crys- 

 tals of mica. When penetrating gneiss the feldspar dyke, 

 if mica bearing, carries muscovite, while the pyroxene dyke 

 carries phiogopite, which is often associated with apatite. 

 This joint occurrence of mica and apatite is quite frequent 

 at certain mines, more especially in the northern Templeton 

 area. 



The origin of the apatite itself has not yet been conclu- 

 sively settled. From its manner of occurrence and associ- 

 ations it would appear to be due to chemical agency rather 

 than to organic. In some of the smaller crystals which 

 occur with mica in the pinkish calcite, the interior is fre- 

 quently found to be composed of pink calcite, itself un- 

 changed to apatite. These frequently penetrate crys- 

 tals of mica, and cracks or fissures in the mica crystal 

 also contain small quantities of the calcite. All pyroxene 

 contains calcite in proportions varying from twenty to nearly 

 thirty per cent., and since its intrusion into the gneiss 

 must have occurred along lines of fracture or least resist- 

 ance, it would appear reasonable to suppose that vapors, 

 charged with some form of phosphoric and fluoric acids, as- 

 cended along such lines. Thus in certain portions of the 

 mass in proximity to the margin of the dykes these vapors 

 would tend to impregnate the softened rock, and in this 

 way through chemical processes, the phosphate of lime 

 might be produced. That the origin of the mineral is 

 deep seated is clearly shown by its presence in the pyroxene 

 at great depths. Thus it has been clearly shown in the 

 working of the North Star mine that the quantity found in 

 the lowest level at a depth of 600 feet from the surface 

 was quite equal to that obtainable from the upper levels, 



