THE OTTAWA NATURALIST. 



Vol. XIII. OTTAWA, MAY, 1899. No. 2. 



THE MINERAL RESOURCES OF THE 

 OTTAWA DISTRICT. 



By R. W. Ells, LL.D., F.R.S.C. 



( Contiiiited front April iimiiher. ) 



While mineral developments are found throughout the 

 Ottawa valley at a number of places, there are two localities in 

 the lower Ottawa basin which have for many years been distin- 

 guished for economic production. Of these, probably the most 

 important, as to output, are the deposits of apatite and mica 

 lying to the north of the Ottawa River and between the rivers 

 Gatineau and Lievre ; the other is situated to the south, in the 

 vicinity of the Rideau lakes, and near the line of the Kingston 

 and Pembroke railway, in which districts our great deposits of 

 iron are located. In the great area occupied by the lower or 

 Laurentian gneiss the mineral developments are, in so far as yet 

 known, few, and it may be generally remarked that investiga- 

 tions along these lines in that area have not yet been very 

 successful. The geological horizons therefore, in the crystalline 

 rocks that promise the best results, and have so far been the 

 most productive, are the upper part of the gneiss and limestone 

 formation and the associated Huronian rocks. 



Now if we carefully study the rock masses in these areas 

 we find a very extensive development of clearly igneous rocks, 

 such as greenstones, granites, pyroxenes, diorites, &c., and it is 

 generally in connection with some of these masses that our most 

 productive mineral deposits may be looked for. The natural 

 inference therefore is that mineral developments are in some 

 way due to the agency of these latter intrusions. 



That many of these intrusive masses are newer than the 

 rocks with which they are associated is clearly shown by the 

 fact that, though they sometimes occur as apparently bedded 

 portions, they quite as often occur cutting the surrounding^ 



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