vanuise.]  LAKE    SUPERIOR    REGION.  61 
Superior  the  Laurentian  rocks  consist  for  the  most  part  of  gray  and  red- 
dish gneiss,  with  micaceous  belts  and  mica-schists.  In  the  same  region 
the  Huronian  rocks  are  mostly  of  a  schistose  character,  the  most  com- 
mon of  which  are  greenish  schists  and  imperfect  gneisses,  which  include 
micaceous,  hornblendic,  dioritic,  porphyritic,  siliceous,  cherty,  chloritie, 
felsitic,  and  argillaceous  schists;  more  rarely  dolomitic  schists,  and 
occasionally  bands  of  magnetic  iron  ore  and  hematite.  Connected  with 
the  Huronian  rocks  are  various  patches  of  granite  and  syenite  which 
show  no  stratification.  In  the  Mpigon  basin  the  Upper  Copper-bear- 
ing rocks  have  their  maximum  development  in  Canadian  territory.  The 
basin  consists  of  marls,  sandstones,  often  covered  with  trappean  out- 
flows. For  this  Upper  Copper -bearing  series  the  term  Mpigon  group 
is  proposed. 
Bell,24  in  1870,  finds  on  lake  Winnipeg  extensive  areas  of  Lauren- 
tian gneiss  and  Huronian  schist.  The  run  of  the  stratification  is  pretty 
uniform,  averaging  from  50°  to  60°  south  of  east,  being  almost  at  right 
angles  to  the  general  strike  of  the  Laurentian  and  Huronian  rocks  in 
the  great  region  north  and  northwest  of  lake  Superior. 
Bell,25  in  1877,  describes  the  rocks  from  the  head  ot  Moose  river  to 
Michipicoten  and  lake  Superior;  also  along  the  Goulais  river.  Before 
reaching  lake  Superior  there  are  several  broad  alternating  belts  of  Lau- 
rentian gneiss  and  Huronian  schist.  The  Huronian  hornblende  and 
mica-schists  are  cut  by  granite  veins  of  various  sizes,  one  of  them  100 
feet  thick.  On  the  Goulais  river  there  are  again  alternations  of  Lau- 
rentian and  Huronian  rocks. 
Bell,26  in  1878,  gives  observations  on  the  geology  of  the  east  shore 
of  lake  Superior  from  Batchawana  bay  to  Michipicoten  river.  The 
Upper  Copper -bearing  series  of  Mamainse  is  calculated  to  have  a  thick- 
ness of  22,400  feet.  It  consists  of  a  great  variety  of  amygdaloids,  vol- 
canic tufas,  felsites,  cherts,  crystalline  diorites,  sandstones  and  coarse 
conglomerates,  the  latter  forming  one  of  the  most  striking  features  in 
the  series  as  it  passes  into  a  bowlder  conglomerate.  The  bowlders  are 
sometimes  crowded  in  a  sandy  matrix,  the  largest  running  as  high  as 
3  feet  8  inches  in  diameter,  but  the  majority  are  under  1  foot.  Far  tbe 
greater  number  consist  of  granite  and  crystalline  schists  like  those  of 
the  Huronian  series,  but  there  are  also  found  white  quartz,  amygdaloid 
and  gneiss.  Granites,  gneisses  and  schists,  as  well  as  basaltic  dikes, 
are  found  at  many  points.  Cape  Choyye  is  composed  of  Huronian  rocks, 
which  consist  of  mica-schists  and  hornblende-schists,  slaty  quartzite, 
and  massive  diorite.  The  rocks  of  Gros  cap  are  mostly  slaty  diorite, 
interstratified  with  siliceous  rock,  in  which  occur  exposures  of  purplish 
red  hematite.  A  dioritic  slate  west  of  Gros  cap  holds  layers  and  len- 
ticular patches  of  felsite  and  also  rounded  pebbles  of  granite,  the 
largest  of  which  are  9  inches  in  diameter. 
Macfarlane,27  in  1879,  in  discussing  Selwyn's  paper  on  the  Quebec 
group,  maintains  that  there  is  frequently  found  between  the  water  and 
