hk. Irving—Oopper-beariny Rocks of Lake Superior. 53 
t 
ontreal River; that they were disturbed by the same force, 
and received their present tilted positions at the same time, as 
evinced by the conformability of the two series throughout. 
2d. That the horizontal sandstones of the Apostle Islands 
and the western end of Lake Superior were laid down subse- 
quently to this tilting, and also to an immense amount of erosion, 
and that the sandstones of eastern Lake Superior were form 
at the same time. ; 
_ As evinced by (1) the occurrence of horizontal sandstones in 
immediate proximity of tilted sandstone and traps, in Ashland 
County ; (2) the occurrence of the same on the Apostle Islands, 
within but a few miles of the tilted beds of the Montreal ; (3) 
the direct actual contact of the horizontal sandstones in Douglas 
County with the melaphyres of the Copper-bearing Series, here 
dipping southward, and (5) various other proofs cited by 
Brooks and Pumpelly in the article previously alluded to. 
8d. That hence the Copper-bearing Series should rather be 
classed with the Archean than with the Silurian. 
*As already shown by Brooks and Pumpelly. 
