GOLD-BEARING VEINS OP BOG BAY 495 



ice-tongne, and that the streams from this tongue built out their deltas into this 

 water on either side. From the facts known at present it is not possible to say 

 just which condition prevailed in the Thames valley. 



Remarks on Mr Gulliver's paper were made by J. B. Woodworth, 



In the absence of the author the following paper was read in abstract 

 by Robert Bell : 



GOLD-BEARIN& VEINS OF BOO BAY, LAKE OF THE WOODS 

 BY PETER MCKELLAE 



{Abstract'] 



Many auriferous veins have been prospected and a considerable number mined 

 in this part of the gold region of western Ontario. Three of the companies operat- 

 ing there, namely, the Tycoon, Toronto and Western, and the Mikado, are working 

 on veins cutting the Bog Bay granite mass. The peculiar feature of these veins is the 

 smallness of the quartz fissures compared with the total size of the orebodiesi and 

 it is this characteristic that the present paper is intended to explain. 



The geology of the whole disti-ict from lake Superior to the west side of lake of 

 the Woods, with a breadth of over 300 miles, has been investigated and the re- 

 sults published in detail by the Geological Survey of Canada. 



Doctor Bell commenced the real work in the Thunder Bay district in 1869, and 

 in the Wabigoon and Lake of the Woods regions in 1881, and made the first geolog- 

 ical maps of these territories. He showed that the rocky of this great area were 

 essentially Laurentian and Huronian, the gneisses and the principal acid erupt- 

 ives being classed with the former, while the green schists in general and the 

 basic eruptives were provisionally included in the latter system. In many places 

 both groups of rocks were shown to be intersected by felsitic and greenstone 

 dikes and numerous fissure veins, many of which are now proving to be aurif- 

 erous. 



The author described, illustrating by diagrams, the three mines above men- 

 tioned and showed that small quartz veins cutting the granite were accompanied 

 on one or both sides by a workable thickness of an auriferous mineral to which 

 he gave the tentative name mikadoite. 



The quartz veins are frequently so small as to be traced with difficulty for any 

 considerable distance on the surface, yet when opened up by mining they gener- 

 ally show a breadth of 2 to 6 feet or more of gold-bearing ore, consisting mostly 

 of this minei'al, which resembles light greenish-gray serpentine, but has a coarse 

 granular fracture like the granite itself. It passes by insensible degrees into 

 quartz, but when pure it is easily distinguished by its softness and the unctuous 

 character of its powder. 



Iron pyrites in very fine grains is disseminated through it to the extent of one-half 

 to three per cent or more, and this vein-mineral may be identical with a similar one, 

 also characterized by fine-grained iron pyrites, which forms parts of some of the 

 gold-bearing veins of the Ural mountains. The weathered surface of the mika- 

 doite resembles that of the adjoining granite, and the outcroppings of these pecu- 

 liar veins would be passed over as unworthy of notice, even by experienced 



