COPPER-BEARING ROCKS OF LAKE SUPERIOR PL. XxIll 
ED STATES GEOLOGICAL SURVEY 
I. 
n 
N. 35° W. throug 
Silver mountain 
Main trap range 
Fault = 
ay » It 5 
Silver af: ler Sandstone 
Keweenaw series, upper deiviston 
Kowveenaw serves , lower adtviston 
Huronian 
I. 
N. 28° W. through Agoge 
Maw range 
bic and Carp lakes. 3 
Fault 
Porcuptnr 
Fauk 
Eastern Sandstone 
Se 
S.E.. 
Heweena SUS 
upper Aiveston 
Keweenan z SETTES 
dower diviston 
lower division Heweenau serves 
upper diviston 
Keweenaw series, 
Laurentian  Huronian 
(Gnewss, granite ete) 
Il. 
N45 W. through the mo 
uth of Montreal river. 
TAKE SUPE 
Keweenaw Serves: 
Muronian Keweenaw sertes 
lower division upper division 
Laurentian 
(@newss qrantte elt } 
IV. 
N.27° W. through Long lake. 
Douglas Co Copper range > 
ea abet Western SEOEN W. 
lake 
Long 
serves, lower division Keweenaw series, upper division Keweenaw vertes, lower division 
Laurentian Huronian  Heweenaw 
( Gnetss, granite ele) 
Ws 
Across the S! Croix valley from Chegwatona t Clam lake. 
fotsdam Sandstone _ 
W. 
Potsdam Sandstone 
A Hoon ® Co SiO. Bainere 
Keweenaw sertes, lower division 
Hurontian 
Se 
THE REGION BETWEEN PORTAGE LAKE AND THE S* CROIX RIVER. 
GENERALIZED GEOLOGICAL SECTIONS OF 
