1869.] MACFARLANE — GEOLOGY 01 LAKE SUPERIOR. 37 



ON THE GEOLOGY AND SILVER ORE OF WOODS 

 LOCATION, THUNDER CAPE, LAKE SUPERIOR. 



By Thomas Macfarlane. 

 Part I.* 



During the summer of 1868, aa exploring party, under my 

 charge, was sent by the Montreal Mining Company to examine 

 their mineral lauds on Lake Superior. On one of their properties, 

 Woods Location, near Thunder Cape, a silver vein of some 

 promise was discovered, and a good deal of attention was paid to 

 the geology of its neighbourhood. The results of my observations 

 are, with the permission of the Directors of the Company, made 

 the subject of the present paper. 



The accompanying map shews the geology of that part of the 

 location lying nearest the lake. 



The stratified or derived rocks which are found upon it, and 

 which are indicated by the five first colours under the word 

 " Reference," belong to Sir W. E. Logan's Upper Copper-bearing 

 rocks of Lake Superior, the age of which is, perhaps, still a 

 matter of doubt. The lowest group of this series found upon the 

 location consists of grey argillaceous sandstones and shales, 

 coloured lilac on the map. A general description of these will be 

 found on page 68 of the Geology of Canada, to which I have 

 to append the following additional particulars. The sandstone 

 layers, varying in thickness from a few inches to several feet, are 

 invariably small or fine-grained, and occasionally shew narrow, 

 indistinctly limited bands of light and dark grey, running in 

 planes parallel with the stratification. A specimen from Location 

 Bay, more closely examined, yielded the following results. Before 

 the blow-pipe it fuses at the edges to a greyish white enamel, and 

 the adjacent parts become lighter coloured and slightly brownish. 

 Hydrochloric acid causes a very slight elFervescence. The powder 

 is slightly reddish, or brownish grey, and on being examined 

 chemically, gave the following results : — 



Silicious matter (insoluble in Hydrochloric Acid and dilute Potash ley). So 09 

 Matrix — 



Protoxide of Iron 4 08 



Alumina 4 • 86 



Carbonate of Lime i 15 



Carbonate of Magnesia o • 56 



Silica 480 



Carbonaceous matter and water (loss on ignition) 1-75 



Alkalis, etc. (by difference) 2-71 



10000 



Interstratified with such sandstones, there are sometimes found 

 • The map will appear with the second part of this paper. — Ed. 



