ON THE SHORES OF LAKE SUPERIOR. D 



In the Porcupine Mountains I have seen works made bj the English miners in 

 the years 17<><) and "70, where an adit or open cut made in the face of a cliff has 

 been always exposed to the frost and rains. But here the marks of picks and drills 

 appear as fresh and as perfect as if they had been recently made, although in some 

 places the sides of the cut are "covered l>\ old lichens and mosses. 



-\r Copjper Falls Location. — The ancient miners made very extensive excavations on 

 the property of the Copper Fails Mining Company, both upon veins and metallife- 

 rous bands, which run parallel with the formations. By the profile and explanations 

 here given the geological structure of the place will be well understood. 



Fig. 3. 



Ea^jev-el^ ig^a^,,^ 







Section on the Copper Falls Vein. Explanations. — W3*F?X= \ Trap rock. [6fo°a°o? | Conglomerate beds. ^4'z-f--=Vrl 

 Sandstone. — a a a. Ancient pits on the vein. — b b 6. Shafts and galleries of the mine. — c. Sand dunes. — d d. 

 Copper bearing bed of trap. 



Scale — horizontal and vertical — 2 inches to the mile. 1, (i, 7, Nos. of the shafts. 



This sketch illustrates the geology of the northern part of the range, or of all 

 mines described under the head of Copper Falls Location. 



From this it will also appear that when we use the term extensive, as applied to 

 " Indian diggings," it is only in a comparative sense, and in reference to other 

 works of the old miners. The levels and shafts constructed by the Copper Falls 

 Mining Company', since 1851, cause the mining of the ancients to appear like mere 

 exploratory pits. 



On looking at the map, the pits will be seen, to occupy a total length of several 

 miles on this location; but none have been reopened that had a greater depth than 

 twenty-four feet, while the modern shaft has already descended more than 250 feet, 

 and the mine has rock galleries of greater total length than all the old trenches of 

 the ancients. In the profile their pits are shaded, and represented at a a «, occupying 

 about half a mile on the "Fast Vein," or as it is sometimes called, the "Copper 

 Falls Vein." Before they were obliterated, as they are in part now, the surface 

 appearance- was that of an irregular channel or trough ascending the mountain from 

 the edge of the sandstone beds to the band d d, which carries copper. Here a 

 system of basin-shaped cavities, broad, circular, and deep, crossed those made on 

 the vein. They are denoted by heavy black dots on the map. 



The first named series were from two to five feet deep and five to ten broad, and 

 the latter five to eighteen deep, with a diameter of twenty to 120 feet. Forest 

 trees and underbrush stood alike within and without them. 



