26 The Ottawa Naturalist. [May 



strata at all angles. It was to some extent, doubtless, this 

 bedded character that led to the original supposition that these 

 masses were, for the most part, sedimentary in their nature, and 

 this \vas the view expressed by most writers on this subject 

 twenty to thirty years ago. 



Apatite. 



If we examine any of the mines of apatite, either to the 

 north or south of the Ottawa, we find this mineral invariably 

 associated with pyroxene, which would therefore appear to be 

 its necessary accompaniment. Now the pyroxene dyke or mass 

 which cuts across the strike of the gneiss or limestone must be 

 of more recent date, and the apatite is generally found along 

 the outer margin or near the lines of contact of the intrusive 

 mass and the gneiss. Frequently, however, masses of calcite, 

 often of large size, and of a pinkish or grey color, are found in 

 the mass of the pyroxene, and this frequently contains large 

 crystals of both apatite and mica, leading to the statement by 

 some observers that these minerals occur sometimes in economic 

 quantity in the crystalline limestones. One must however dis- 

 criminate between masses of calcite which are an integral 

 portion of the pyroxene dykes, and the limestone formation 

 proper, which is an entirely different thing, so that it may be 

 safely stated as the result of the examination of all the known 

 mines of this mineral, that apatite is not found except in asso- 

 ciation with pyroxene. 



As to the origin of this mineral opinions differ, but it is 

 found generally in one of two ways, either as large pockety 

 masses, which sometimes yield a thousand tons or more, or as 

 irregular developments varying in width from a few inches to 

 several feet in thickness. The extent and value of this one of 

 our mineral resources of the Ottawa district, may be gathered 

 from the statistics contained in the official bulletins of the 

 Geological Survey. Thus we find that, in the seventeen years 

 from 1878 to 1894, the output of this mineral from the mines of 

 eastern Ontario was 24,760 tons, with a market value of 260,974 



