CANADIAN APATITE. 31 



bears to many others, e.g., pyroxene, beryl, etc., it having often 

 been mistaken for these by mineralogists and miners. 



Essentially, it is a tricalcic phosphate, its chemical composition 

 being represented by the formula 3Ca3(P04)2CaF._,. This formula 

 shows the presence of calcium fluoride, which in our Canadian 

 species amounts to about 7%. In many European species this is re- 

 placed by a somewhat larger percentage of calcium chloride. This 

 fact makes our apatite the richer in phosphoi'ic acid of the two, as 

 the following figures will show : — 



Canadian fluor-apatite 3Ca3(P04).,CaF2 1 Qg^p^ *"...!.. 7.74* 



European chlor-apatite . . . . 3Ca3(P()4)CaC1.2 1 CaCl * ^ ...... 10.68 



These percentages have been calculated from the molecular for- 



mulae. 



We find, however, that a small amount of the calcium fluoride is 



as a rule replaced by calcium chloride, and that the percentage of 



tricalcic phosphate is lowered by the presence of calcium carbonate 



to an extent of from .05 to 5%, apparently present in thin laminae in 



the cleavage planes. 



The analysis of a specimen from the Templeton district, of a fair 



average quality, shows it to have the following composition : — 



Tricalcic phosphate 89.85 



Calcic fluoride 7.90 



Calcic chloride 37 



Calcic carbonate 49 



Insoluble residue 05 



Note. — The difierence, 1.34%, may be partly accounted for by the 

 presence of moisture, and partly by the presence of small quantities 

 of alumina and magnesia not estimated in this case. 



The rocks in which this mineral occurs belong to the Laurentian 

 period. They cover a vast area both in Ontario and Quebec, over- 

 lying a district in the northern portions of these P)-ovinces from 

 Labrador to the Arctic Ocean, and stretching down to the St. Law- 

 rence between Kingston and Brockville. For the most part this 

 district is exceedingly wild and rugged, often densely wooded, though 

 in many places overlaid by rocks of the Palfeozoic Age and by 

 glacial and post-glacial deposits, where agriculture to a greater or less 



