20 



workable deposits of this mineral before passing to the oldest of fossil- 

 iferous systems, the Laureiitian. 



The rocks of this formation are among the most ancient on the 

 North American continent and probably correspond to the oldest gneiss 

 of Scandanavia. The modes of occurence are so varied in the Cana- 

 dian Apatite field, that the subject would require to be treated by itself 

 in order to do it justice lieie. 



We are all here familiar with how it is found, both in Ontario and 

 Quebec provinces. 



Dr. Hunt thus describes in 1884, the main features of its mode of 

 occurence : " The deposits of Apatite are in part bedded or interstratified 

 in the pyroxenic rock of the region, and in part are true veins of poste- 

 rior origin. The gneissic rock with their interstratified quartoze and 

 pyroxenic layers, and an included band of crystalline limestone, have a 

 general northeast and southwest strike, and- are much folded, exhibiting 

 pretty symmetrical anticlinals and synclinals, in which the strata are seen 

 to dip at various angles, sometimes as low as 25 degrees or 30 degrees, 

 but more often approaching the vertical. The bedded deposits of 

 apatite, which are found running and dipping with these, I am disposed 

 to look upon as true beds, deposited at the same time with the enclosing 

 rocks. The veins, on the contrary, cut across all these strata, and in 

 some noticeable instances, include broken angular masses of the enclos- 

 ing rocks. They are tor the most part, nearly at right angles to the 

 strike of the strata, and generally vertical, though to both of these con- 

 ditions there are exceptions. One vein, which had yielded many 

 hundred tons of apatite, I found to intersect, in a nearly horizontal 

 attitude, vertical strata of gneiss, and in rare cases what appear, from 

 their structure and composition to be veins, are found coinciding in 

 dip and in strike with the enclosing strata." 



The apatites of Norway are known since 1854, and occur on the 

 southern coast in similar rocks to our own (Canadian), and many of the 

 associated minerals are similar to those observed in the Laurentian 

 rocks, the vein matter differing chiefly in freedom from carbonate of 

 lime. 



Rutile may be mentioned as an exception, which in some mines is 

 so abundant as to form a considerable revenue to a working mine, since 



