LAKE    SUPERIOR   REGION. 
319 
The  general  succession  for  the  Lake  Superior  region  is  given  as 
follows : 
Correlation  table  of  N.  H.  Winchell,  1895. 
St.  Croix. 
Upper  Cambrian 
(Olenellus  zone). 
Eastern  sandstone. 
Lake  Superior  sandstone. 
Nipigon  formation. 
© 
"53 
(The  Dicellocephalus— "Potsdam"  of  New  York.) 
3 
to 
SI 
Keweenawan.    Traps  and  underlying  quartzite  and  con- 
> 
'33 
CO 
0) 
s  §  i 
glomerate. 
* 
Kewee 
{Parao 
ZOI 
Potsdam  at  Potsdam,  N.  Y.,  and  eastward  to  Ausable 
River. 
Unconfc 
>rmity. 
Taconic  (or  middle  and 
"3 
Animikie  slates. 
lower  Cambrian). 
| 
Pewabic  and  Wauswaugoning  quartzites. 
Penokee  series. 
Mesabi  iron  range. 
S    2   *& 
Misquah  Hills. 
Gabbro  and  anorthosite  range. 
<  , 
Norian. 
s. 
Upper  Laurentian. 
e 
Bohemian  range  and  South  Copper  range  in  Michigan. 
o 
Minong  range,  Isle  Royal. 
The  great  unconformity. 
Archean. 
Ontarian. 
Keewatin. 
Coutchiching. 
Laurentian. 
The  following  general  conclusions  are  reached  as  to  the  Lake  Su- 
perior region  and  other  parts  of  the  United  States: 
The  rocks  of  the  Cortland  series  (the  elastics),  of  the  original 
Taconic  area,  and  of  the  upper  series  of  the  Adirondacks  are  of  the 
same  age — i.  e.,  Taconic,  or  lower  Cambrian. 
The  basic  rocks  of  the  Norian,  or  Upper  Laurentian,  system  of 
Canada  are  of  the  same  age  as  the  gabbros  of  the  Adirondacks. 
The  Taconic  in  America  embraces  all  the  strata  containing  any 
known  fossils  older  than  those  in  the  Dicellocephalus  or  Upper  Cam- 
brian.    It  is  separated  from  the  Archean  by  a  profound  unconformity. 
The  Animikie  strata  in  Minnesota,  and  in  general  the  upper  iron- 
bearing  series  of  the  Lake  Superior  region,  are  of  the  age  of  the 
Taconic, 
