9 6 



There are also blind veins, e.g., one that was worked two 

 or three years ago under Peterson lake and one on the Silver 

 Leaf property, that lie in Keewatin beneath the sill. These 

 veins run upward to the lower face of the sill but not into it. 



The types of veins mentioned in the preceding para- 

 graphs are shown in the accompanying, generalized cross- 

 section of the area. 



RELATION OF WALL ROCK TO ORL. 



The productive veins, as the maps and cross-sections 

 show, are found in three series of rocks, viz. : the conglom- 

 erate and other sediments of the Cobalt series, the Nipissing 

 diabase sill, and the Keewatin complex. But eighty per 

 cent, or more of the ore has come from the Cobalt series. 

 The chief reason for this greater productiveness is due to 

 the fact that these rocks fractured more readily than did the 

 diabase or the Keewatin. 



There appears to have been no difference in the pre- 

 cipitation of ores due to physical-chemical influences of the 

 country rocks. Precipitation seems to have taken place as 

 readily in rocks of any one of the three series mentioned in 

 the preceding paragraph as in the others. 



Judging from the way in which silver is found in the 

 minutest cracks in granite boulders of some of the con- 

 glomerate near the veins, this ore. at least, was precipitated 

 no less readily in acidic rocks than in basic ones. With the 

 exception of these boulders, there are few opportunities 

 afforded of observing the relations of the ore to granite. 

 But in the Temiskaming mine, a few hundred feet below the 

 surface, narrow dikes of Lorrain granite intrude the 

 Keewatin and are cut across by a vein. The surface of the 

 granite is plated with native silver. 



The occurrence of rich silver ore depends on the char- 

 acter of the openings in the rocks now occupied by 

 the veins, on whether the veins have been affected 

 by secondary disturbances, and on the proximity of 

 the openings to the diabase sill. Naturallv it would 

 be expected that solutions would work upward through 

 the openings in the hanging wall above the sill more 

 readily than downward into the foot wall. Unfortun- 

 atelv owing to the excessive erosions to which the district 



