Copper-bearing Rocks of Lake Superior. 321 
_ The character of this overlap is exhibited in the accompany- 
Ing wood cut (fig. 1) of a vertical section of the neighborhood 
1.—Section from Montmorenci to Orleans Island, 
Montmorenci. North Channel. Orleans Island. 
hy uu a4 g 
a ¢ 
u g 
_ Horizontal and vertical seale, 1 inch to a mile. g, Laurentian gneiss; ¢, Trenton 
; u, Utica and Hudson River formations; g, Quebec group; F, Fault; 
9, Overlap ; S, Level of the Sea. 
of Quebec, extending from the Montmorenci side of the St. 
ence across the north channel and the upper end of the 
one bound to the foot of the precipice, which, immediately 
hind the water, is composed of this rock. At the summit, the 
‘ Trenton be bank 
have a thickness of about fifty feet, and are marked by the 
Sceurrence of Leptena sericea Sowerby), Strophomena alternata 
(Conrad), Orthis testudinaria A er, n 
| same thickness o limestone is tilted up to an angle of 
] fifty-seven degrees, This is followed by about an equal amount of 
es a e chasm on each side. pe are oe age 
ght feet of h ti eathering brown, 
— pieced La os ratified with black shale. On 
| . & ig about a quarter of a mile, and the dip, which is towards 
