nhisb.]  LAKE    SUPERIOR   REGION.  123 
Chester,165  in  1884,  describes  the  rocks  of  the  Mesabi  andVerioilion 
hi  ranges.  The  slates  and  schists  on  the  south  side  of  the  Mesabi 
uge  are  nearly  horizontal.  The  rocks  here  found  are  precisely  like 
ose  of  the  Penokee  region  of  Wisconsin,  and  the  two  series  bear  the 
me  relation  to  the  Huronian  series.  The  iron  ore  at  Vermilion  lake 
found  in  connection  with  jasper  and  qnartzite  and  is  intimately 
tflded  with  the  country  rock,  chiefly  sericite-schist,  standing  in  nearly 
perpendicular  position.  These  rocks  are  the  representative  of  the 
ichigan  and  Wisconsin  iron  deposits,  and  there  is  no  doubt  that  they 
dong  to  the  Huronian.  The  Vermilion  deposits  bear  the  same  rela- 
ms  to  the  granite  as  do  those  of  Mesabi,  and  they  are  regarded  as  the 
me  formation. 
Winghell  (N.  H.),166  in  1884,  gives  the  general  succession  of  rocks 
northeastern  Minnesota,  in  descending  order,  as  follows:  (1)  Pots- 
im,  including  the  Keweenawan  sandstones,  shales,  and  conglomerates, 
Langed  by  igneous  gabbros  and  dolerites  locally  to  red  quartzites,  fel- 
tes,  quartz-porphyries,  and  red  granites.  (2)  Taconic  group,  includ- 
g  the  Animikie  series,  the  Gunflint  beds,  the  Mesabi  iron  rocks,  the 
^ishki  Manissi  conglomerate  (?),  the  Thompson  slates  and  quartzites, 
id  the  Vermilion  iron  rocks.  (3)  Huronian  group  (?),  including  mag- 
ssian  soft  schists,  becoming  syenitic  and  porphyritic,  found  on  the 
>rth  side  of  Gunflint  lake,  along  the  national  boundary,  and  at  Ver- 
ilion  lake.  (4)  Montalban  (  ?),  including  mica-schists  and  micaceous 
anites  about  Vermilion  lake  and  on  the  Mississippi  river.  (5)  Lauren - 
m,  including  massive  hornblende- gneiss  and  probably  the  Watab  and 
j.  Cloud  granites.  This  succession  is  parallelized  with  those  of  other 
citers  given  for  the  northwestern  States. 
Winchell  (X.  H.)  and  Upham,167  in  1884  and  1888,  give  detailed 
iological  maps  and  descriptions  of  many  of  the  counties  of  Minnesota, 
hich  include  the  Laurentian  gneisses  and  granites  of  the  Mississippi 
id  Minnesota  rivers,  the  slates  of  the  Upper  Mississippi,  the  quartz- 
es and  conglomerates  of  Cottonwood,  Pipestone,  Rock,  Brown,  and 
[collet  counties,  which  are  regarded  as  Potsdam  sandstone.  The  cop- 
ir-bearing  traps  and  conglomerates  of  Chisago  and  Pine  counties  are 
aced  as  Lower  Cambrian.  These  reports  contain  nothing  as  to  struc- 
ral  relations  not  found  in  the  annual  reports. 
Winchell  (N.  H),168  in  1885,  finds  between  Two  harbors  and  Ver- 
non lake  two  rock  ranges,  the  first  being  Mesabi  proper  and  the 
cond  the  Giant's  range.  Resting  unconformably  upon  the  syenites  of 
ant's  range  are  the  Huronian  conglomerates  and  greenstones  of  Ver- 
lion  lake,  l^rile  south  of  this  range  are  the  slates  and  quartzites  of 
Animikie,  i:l  verlain  by  the  gabbro  and  red  granite  of  the  Mesabi 
»e,  which  is  in  turn  overlain  by  the  trap  rocks  of  the  Cupriferous 
ies.  The  Huronian  is  represented  as  resting  conformably  below  the 
rimikie,  although  not  appearing  at  the  surface.  There  are  three  iron- 
horizons,  the  titanic  iron  of  the  gabbro  belt,  the  iron  ore  of  the 
