THE LAKE SUPERIOR SYNCLINAL. 
speculation that this fault is met at a large angle by 
another, coming from the southeast, at a point behind 
the line from the end of Keweenaw Point to Stannard’s 
Rock, the junction of the two being the lowest part of 
the dislocation. Behind the Porcupine Mountains, as 
previously shown, is again a fault, of much smaller ex- 
tent, which is again connected with a fold, though a sub- 
ordinate one. I have also already indicated the prob- 
ability of the existence of a fault on the north side of the 
Douglas County Copper Range of Wisconsin. The 
connection of the belts of this range with those of the 
North Shore is one of the least satisfactory parts of the 
map of Plate XXX. It is evident, however, from the 
trends on the North Shore, and in the Douglas County 
rock belts, that some such connection must exist, though 
whether with so much of a fold as I have indicated is 
not so plain. 
The relation of the Huronian to the synclinal is a 
point of great interest. Beyond question, in the western 
half of the Lake Superior basin, it bottoms the great 
trough, for its beds are found dipping inwards on both 
sides; on the North Shore at a low angle, and on the 
south generally at a high one. It appears highly prob- 
able that the eastern part of the trough is similarly bot- 
tomed by the Huronian. The Huronian beds are, how- 
ever, here found, just without the rim of the synclinal, 
folded in a complicated manner; for instance, beyoud 
the western end of the trough in Minnesota, in the iron 
regions of Michigan, on the east shore of Lake Supe- 
rior, and about the head of Lake Huron. Other folded 
schists, which possibly belong with the Huronian, 
occur in Canada, north of Lake Superior. The con- 
nection of these folded beds with the unfolded is a 
structural problem still needing investigation. So far 
27 LS 
‘usu doledng oyv7yT JO UoMoas [voeTodAyT—' ge “DIT 
7 
oly 
ee 
swrips 
nf 
Aeopuoanyy PIPT0T 
~ 
ti 
Xf 
S 
\ 
‘SISNPS' 
MDPUOLNIT DP] OT 
