49 



suraaulj comes, to a very large extent at least, from quartz veins in the 

 Cambrian slates and quartzites, though it may also occur in limited 

 quantity in the Cambro-Silurian, and has been detected in metalliferous 

 lodes in the older crystalline schists. The asbestus is almost entirely 

 confined to the serpentines of the volcanic portion of what has been 

 styled the Lower Cambrian, and which occurs probably as an alterative 

 product from dioritic rocks, rich in olivine. The serpentine is generally 

 associated with slates and hard sandstones of that system. The chromic 

 iron is also confined to this belt of rocks. The silver ores, which, in 

 places, carry a fair percentage of gold, apparently belong to the same 

 horizon as the auriferous quartz veins, though small deposits of 

 argentiferous galena are found with rocks of the upper part of the 

 Silurian system in Grasp6 ; while the ores of antimony occur in a series 

 of slaty and micaceous schists which are either low down in the Cam- 

 brian or lie near the summit of the underlying system. 



The sources of mineral wealth more especially prominent at the 

 present time in Eastern Quebec, and about which the greatest amount of 

 interest is centred, are three in number, viz , copper, asbestus and gold, 

 and as these bid fair to increase annually in importance, a brief glance 

 at their history and geological relations may be of interest. 



The first official reports on the copper deposits of the Eastern 

 Townships by the Canadian Geological Survey were made by the late Sir 

 "VV. E. Logan, in 1847, when attention was directed by him to the 

 occurrence in the townships of Ascot, Upton and Inverness of that 

 mineral, which places were recommended by him as localities for trial. 

 Explorations proceeded rapidly and resulted in the location of numerous 

 mines at various points, principally in what was then regarded as the 

 metamorphic portion of the series, subsequently styled the Quebec 

 group, and more especially in what was afterward regarded as the 

 middle and upper divisions of that group, viz., the Lauzon and Sillery 

 formations. These rocks were at that time supposed to be arranged in 

 a series of generally parallel synclinals, extending north-east and south- 

 west. In the first or more westerly of these were placed the copper 

 areas of Roxton, Upton and Acton ; in the second, those of Durham, 

 Tingwick, Inverness, Chestei', Halifax and Leeds ; while the third, 

 together with what was regarded as the double synclinal of Sutton 



