KAMANISTIQUIA SILVER-BEARING BELT. 247 



charactei', underneath the fine-grained trap diabase or siliceous like 

 slate is found, while in the town of Port Arthur itself along the lake 

 shore, another layer of coarse-grained trap is found. There seems to 

 be only the one solution to these layers — different periods of overflow 

 and subsequent cooling. Or, it may be possible that a fault or slip 

 may have extended along the country from McKay Mountain to 

 White Fish Lake, but of this I have no satisfactory evidence. Some 

 of the trap contains Magnetic Iron Ore and it all holds water, some 

 Manganese also Fe O, and large percentage of silica. 



Through the valleys at the foot of the bluffs a heavy layer of hard 

 pan or clay lies ; this has been formed no doubt from the fallen trap 

 which has gradually become disintegrated or decomposed. It is in 

 places sixty or seventy feet deep ; underneath this lies the trap again 

 which would look as if depressions or faults had indeed occurred in 

 the country. The thickness of the trap vaiies from ten to a hundred 

 feet or more, and it rests unconformably on the slates. These slates 

 vaiy in hardness as I am informed by the miners who drill every 

 little distance very markedly. They are dark black, holding consider- 

 able free carbon, so that where slakensides or slips are observed the 

 free carbon rubs off on the hand. Iron pyrites is scattered through 

 them to some extent and a very singular occurrence are the nodules, 

 boulders, or concretions of a hard crystalline character occurring 

 through them. These are usually crystalline and hai-d resembling 

 trap and having frequently in their centre iron pyrites, or a more 

 coarsely crystalline mineral resembling asbestos. While they are 

 usually crystalline I have observed them of a laminated texture 

 resembling the slates as well. Sometimes the iron pyrites is dis- 

 seminated irregularly through them. They weigh from a few ounces 

 upwards to two or three tons. I am unable to offer any satisfactory 

 theory regarding their formation. 



Small nodules of iron pyrites ai-e also quite common, presenting 

 no radii) 1 structure as observed in the iron pyrites nodules occurring 

 in the chalk in the South of England. These slates are laminated or 

 bedded, they yjresent no slaty cleavage, nor are they very often 

 thrown up or distoi'ted, usually lying hoi'izon tally. Thei'e are three 

 groups of veins situated in this belt — one at Whitefish Lake, con- 

 stituting the Silver Mountain group; another at the Beaver Mine, 15 



