vanhise.]  LAKE    SUPERIOR   REGION".  59 
that  a  more  extended  and  detailed  investigation  of  the  structure  would 
show  that  there  is  in  reality  a  very  considerable  break  between  the 
Lanrentian  gneiss  and  the  overlying  schistose  and  slaty  strata  referred 
to  the  Huronian  rocks.  The  evidence  as  to  the  age  of  these  latter  is 
not  satisfactory.  They  resemble  as  closely  the  altered  rocks  of  the 
Quebec  group  as  they  do  the  Huronian  of  lake  Huron  and  Superior. 
Bell,'9  in  1873,  finds  in  the  country  between  lake  Superior  and  lake 
Winnipeg  rocks  belonging  to  the  Laurentian,  Huronian,  and  Upper 
Copper-bearing  series.    The  southern  shores  of  lake  of  Mille  Lacs  are 
composed  of  Huronian  strata.     The  Laurentian  gneiss  and  Huronian 
schists  at  many  places  alternate  with  each  other.     The  junction  of  the 
Laurentian  rocks  on  the  north  with  the  Huronian  schists  on  the  south 
occurs  at  Eat  portage  on  the  lake  of  the  Woods.    The  two  rocks  are 
[seen  almost  in  contact  with  each  other  and  have  the  same  strike  and 
ip.    The  rocks  classified  as  Huronian  consist  principally  of  a  great 
ariety  of  crystalline  schists-  in  which  a  greenish  color  prevails.    In 
ddition  to  these  are  grayish  quartzites  and  schists,  sometimes  with 
rou  ore,  diorites,  imperfect  gneisses.    The  areas  of  granite  and  syenite 
n  the  region,  which  vary  from  patches  to  areas  many  miles  in  length, 
ire  always  more  or  less  intimately  connected  with  the  Huronian  bands. 
he  distinction  between  the  Laurentian  and  Huronian  rocks  is  chiefly 
)f  a  lithological  character,  the  Huronian  appearing  to  succeed  the 
Laurentian  conformably.    The  Upper  Copper-bearing  series,  composed 
jf  slates,  marls,  sandstones,  and  traps,  lie  nearly  horizontally  on  the 
3dges  of  the  Laurentian  and  Huronian  rocks. 
Hunt,20  in  1873,  applies  the  name  Animikie  group  to  the  lower  divis- 
ion of  Logan's  Upper  Copper-bearing  series  of  lake  Superior  as  it  occurs 
at  Thunder  bay,  where  it  includes  dark  colored  argillites  and  sandstones 
overlain  with  a  slight  discordance  by  red  and  white  sandstones  appar- 
ntly  the  same  as  those  of  the  Keweenaw  district.  The  dark  colored 
sediments  of  the  Animikie  group  rest  directly  upon  the  edges  of  the 
3iystalline  Huronian  schists  and  are  cut  by  great  dikes  of  diorite.  The 
great  Keweenaw  group,  with  its  cupriferous  amygdaloids,  is  here  absent, 
Although  met  with  a  few  miles  to  the  eastward.  This  group,  as  shown 
oy  Brooks  and  Pumpelly,  occupies  a  place  between  the  Huronian  schists 
and  the  nearly  horizontal  red  and  white  sandstone  of  the  region,  which 
is  itself  below  the  Trenton  limestone. 
Bell,21  in  1874,  in  the  country  between  the  Red  river  and  the  South 
Saskatchewan,  finds  extensively  mica-scliists  and  gneisses ;  but  a  broad 
Dand  of  schist,  having  the  character  of  the  Huronian  formation,  crosses 
me  central  part  of  Bainy  lake.  On  the  islands  of  the  lake  of  the  Woods 
:he  granites,  gneisses,  and  Huronian  schists  are  intricately  mingled  with 
Bach  other. 
Dawson  (G.  M.)22,  in  1875,  gives  an  account  of  the  geology  of  the  lake 
j)f  the  Woods,  where  the  rocks  are  wholly  Laurentian  and  Huronian. 
The  Laurentian  formation  is  represented  by  a  great  thickness  of  granit- 
