34 PROCKEDINGS OF THE CANADIAN INSTITUTE. 



impurities mechanically mixed with the minerals. Thus the red and 

 brown varieties contain minute crystals of hematite ; the blue and 

 green, scales of chlorite ; and the yellow and violet owe their tints 

 to organic substances. 8ome few years ago crystals were a rarity, 

 as much as $5 being paid for one with good edges and terminations, 

 though of small size ; now they ai-e so plentitul as to be practically 

 valueless as specimens. 



It would be well to mention here the so-called nodules, which 

 appear to have been crystals, subsequently subjected to partial fusion, 

 so that all exterior resemblance, except in size and rough outline, 

 has been lost. It is possible that i-ounding of the edges is due to the 

 solvent action of steam at high temperatures and pressure. 



It is in the massive condition, as obtained fi'oni veins and " stocks" 

 or " pockets," that it is extensively mined. 



For some yeai's it was supposed that apatite did not occur in true 

 veins, but a study of the Templeton district has proved that such is 

 the case. At Mud Bay, Lake McGregor, this is clearly shown by 

 the phosphate deposit cutting the strike of the containing I'ocks ; 

 and again, in the same neighbourhood, there is a vein that has a true 

 banded structure, the gangue consisting of alternating layers of cal- 

 cite and mica and pyroxene. Examples ai*e not wanting of veins 

 consisting of alternate layers of pyroxene and a})atite. 



The veins ai-e of various dimensions. Traversing the dead rock — 

 limestone, pyroxene, &c. — they narrow and widen with great sudden- 

 ness, and are characterized by an uncertainty of yield,— it being 

 impossible to predict, by any formula, the " out-put " obtainable from 

 any vein. The surface appearance may promise an abundant harvest, 

 but at a few feet below the vein may become entirely " pinched " 

 out. It is only right to add that the reverse of this has proved true 

 — the vein increasing in width at the depth of a few feet. It is not 

 uncommon to notice the phosphate in a vein, with an average width 

 of say three feet for a depth of six or eight feet or moi^e, suddenly 

 narrowing to a thin streak only an inch or two in breadth. This 

 may continue without much alteration for a further depth, and sud- 

 denly enlarging to a size equal to that of the upper deposit. 



In some instances, large amounts have been obtained from veins — 

 one in this district yielded eight hundred tons. It was situated on 



