296 PROCEEDINGS OP THE CANADIAN INSTITUTE. 



Laurentian rocks. In the immense northern Laurentian country to 

 "which I have referred, and which occupies many hundreds of thou- 

 sands of square miles, no limestone bands have yet been detected, 

 although it is probable that other areas of the higher portions of the 

 series containing such bands may yet be found. The Laurentian 

 areas at pi-esent known to hold these limestones lie along the southern 

 parts of the Dominion between the French and the Saguenay Rivers. 

 Limestones are also found in i-ocks classified as Laurentian in Cape 

 Breton and Newfoundland. In the apatite regions the gneisses of 

 some of the bands are less crystalline than the primitive varieties 

 above described, and they are recognizable throughout by certain 

 peculiarities of color, composition, &c. They are seldom so much 

 disturbed as to prevent them from being traced out upon the ground. 

 While the common Laurentian gneiss holds but a small variety of 

 minerals, the rocks of the apatite regions have already yielded up- 

 wards of sixty species. Both in the county of Ottawa and in the 

 Perth and Kingston regions there are several wide bands of crystal- 

 line limestone rudely parallel to one another and separated by great 

 thicknesses of gneissic strata. These are similar to the thick bands 

 of limestone in the gneisses of the county of Argenteuil, which were 

 so carefully traced out in all their windings by the late Sir W. E. 

 Logan between the years 1854 and 1862. Apatite has been found 

 in vai'ious places in this region, but apparently not in paying quan- 

 tities so far as is yet known. 



Besides the limestones, the Laurentian rocks of the apatite regions 

 have associated with them bands of schists, slates, pyroxenite, 

 quartzite, jasper, etc., and they also contain serpentine, graphite, 

 pyrite, pyrrholite and ores of iron, copper, lead and other metals. 



Coming now to the closer associations of the apatite itself, we find 

 that it is almost invariably accompanied by pyroxenite, which may 

 be either coarsely or finely crystalline and of any shade of green, 

 greyish-green, and grey. A somewhat coarsely crystalline orthoclase 

 rock, generally very light grey in color and spotted and mottled with 

 pink, lilac and neutral grey is generally found with the apatite, es- 

 pecially in the valley of the Riviere du Li^vre. The other minerals 

 most commonly associated with it are dark mica, which in most cases 

 is biotite, but may occasionally be phlogopite, pyrite, white, red, 

 pink, flesh and salmon colored calcite. 



In some localities, as in the township of Wakefield, the apatite is 



