430 * DEEP MINING IN NOVA SCOTIA— PKEST. 



Of Post-Carboniferous denudation the greater part seems to 

 have taken place in Pre-Triassic times ; but as this does not seem 

 to have affected the auriferous rocks to any great extent, I shall 

 pass it. 



The " Great Ice Age " of Post-Tertiary times once occupied in 

 text-books a prominent position as an erosive agent, but the 

 investigations of modern glacialists seem to have limited its 

 action considerably. The denudation of the Lower Carboniferous 

 of Musquodoboit and the Triassic sandstones of the Annapolis 

 Valley reaching through Mesozoic, Cenozoic and Glacial times is, 

 as far as my observations go, limited to a depth of not over 300 

 feet. How much of this can be ascribed to the Glacial age is 

 impossible to determine. Unless the " Great Ice Age " has 

 removed a former carboniferous covering from the auriferous 

 rocks I can see no indications of extensive Post-Tertiary ice 

 action over southern Nova Scotia. 



Classification of Mines. 



Our gold mines are of three classes : 



1st. Those consisting of bedded or main leads. 



2nd. Those consisting of cross or fissure leads, or whose gold- 

 bearing main leads are mineralized from fissure leads. 



3rd. Those consisting of gold-bearing drift or conglomerate. 



Those of the 1st class reached no higher than their junction 

 with the apex of the anticline, and were covered by the upper 

 beds before denudation was carried that far. To this class 

 belong the most of our gold mines and auriferous localities. 



Those of the 2nd class cutting across quartzite and slate alike, 

 and not controlled by anticlinal influence, were probably first 

 uncovered by the denuding agencies. To this class belong the 

 mining localities of Brookfield and Broad River, Queen's Count}^ 

 West Rawdon, the Lake lead of Caribou, Upper Cornwall, Lunen- 

 burg County, the Kempt mine, Yarmouth County, and probably 

 South Uniacke and a few others. Those of the 3rd class are 

 the results of the erosion of tlie Lst and 2nd class. They denote 

 that the upper part of a gold-bearing zone has been removed, 



