Macfarlane on the Acton Coj^per Mine. 



455 



erable joints, and veins of calcspar, which ramify through the 

 limestone in all directions. Judging however from the position 

 which a certain narrow band of schistose limestone occupies, it 

 appears as if the limestone of the east slope of Williams's pit 

 was stratified as sketched in the preceding section. 



Between Williams's pit and Pike's pit there existed, as already- 

 mentioned, previous to January, 1862, an arch of limestone; which 

 was perhaps the most picturesque feature of the mine. During 

 the winter, a large quantity of water having accumulated in Wil- 

 liams's pit, and become frozen over, it was judged advantageous to 

 take down the arch, while the access to it by means of the ice was 

 convenient. The piece of ground on the south side of the arch 

 abutting against a huge mass of greenstone, together with the 

 rock above the arch, contained 770 cubic yards = 96 cubic fathoms 

 nearly. These produced : 



tons first quality ore of 23.0 percent. 

 « crush " 4.7 " 



{( u u 2.7 " 



which quantities correspond to 69 J tons of 12 per cent ore. 

 Consequently, a cubic fathom of this rock gave 0.72 tons of 

 12 per cent ore. The cost of mining and hauling was 8o39, or 

 $5.61 per cubic fathom, and 87.75 per ton of 12 per cent ore. 

 The following is a section of the limestone and the adjoining rocks, 

 at this point, as seen from the north-east side, previous to the ex- 

 cavation : 



Section along the line e—f of the general plan. 



S.E. 



N.W. 



The letters denote the same rocks as in former sketches. The 

 dotted lines show the piece of ground mentioned above. It will 

 be observed that here also there exist evidences of foldings in the 



