C. Whittlesey—Pre-Glacial Channel of Eagle River. 393 
DISCOVERIES IN THE PROGRESS OF MINING AND INTERPRE- 
TATION OF THE RESULTS. 
these fragments a reliable plat, which should show the state of 
the old works. I did not ascertain how much of the material 
that related to the first three years of their operations under 
the old charter was preserved by the Company’s agents in 
Boston. 
The works were so singular as to interest every one acquaint- 
ed with mines or mining geology; and there were, in those 
first developments, certain facts shown that were of economic 
value as well as scientific interest. But my object in bringing 
together on one map-sheet the information left by Superinten- 
dent Coryell was at first one of mere curiosity. The plan and 
_ Sections, which ‘were thus produced, show, I think, all the 
Material features of the old works, and represent them in very 
nearly their correct positions and proportions. They are 
Sufficiently full and well explained on the sheet itself, so that 
little remains to be said in reference to the mine-work proper. 
have connected with the plans, such geologic profiles as are 
hecessary to illustrate the ancient state of things; and have 
laid down the different beds of trap rock which originally 
held the copper, that was found in the form of water-washed 
bowlders, 
After the shaft marked No. 2 on the map had been sunk in 
the rock near the bank of Eagle River, to the depth of 62 feet, 
& cross cut was made to the east from the bottom of the shaft. 
This was done to explore the ground. To the great astonish- 
ment of every one, the miners, at a distance of about 20 feet 
from the foot of the shaft broke through into sand and gravel. 
This was 32 feet below the channel of the river (really but a 
creek, at this point), where the water was then flowing. It hap- 
- pened, also, to be on a level with the bottom of the drift-filled 
rge ; so that the miners proceeded along its rocky floor in the 
Ope of further discoveries. A few feet forward, they cut the 
back of a well defined vein. A mass of earth, bowlders and 
gravel lay on either hand and overhead, and was so compact 
as to stand firmly as the gallery prog . Captain aul 
thinks it remains so now, although very little timber was put in, 
