GREAT    NORTHERN    INTERIOR   OF    CANADA.  547 
According  to  Low,  the  central  part  of  the  Labrador  Peninsula  is 
very  largely  occupied  by  "  Laurentian  "  rocks,  with  "  Huronian  ?' 
rocks  consisting  of  altered  sediments  and  basic  and  acidic  igneous 
rocks  in  subordinate  quantity.  In  the  northern  part  of  the  peninsula 
are  schists  and  gneisses,  supposedly  representing  a  bedded  series 
similar  to  the  Grenville  series. 
On  the  east  coast  of  Hudson  Bay  and  in  various  parts  of  Labrador 
is  a  series  of  comparatively  unaltered  sediments  containing  beds  of 
magnetic  iron  ore.  In  the  past  these  have  been  supposed  to  be  above 
the  "  Huronian  "  and  "  Laurentian  "  rocks  of  this  area,  and  accord- 
ingly have  been  mapped  as  "  Cambrian  "  and  correlated  with  the 
Animikie  of  the  Lake  Superior  region.  Low  now  concludes  that 
these  rocks  are  but  less  metamorphosed  phases  of  the  "  Huronian  "  or 
"  Laurentian  "  rocks  and  are  to  be  equated  with  the  iron-bearing 
series  to  the  west  of  Hudson  Bay  and  with  certain  of  the  iron-bearing 
series  of  the  Lake  Superior  region,  the  superior  position  of  the  rocks 
on  the  shore  of  Hudson  Bay  being  explained  by  faulting.  He  had 
previously  called'  attention  to  the  similarity  of  the  succession  on 
Richmond  Gulf,  on  the  east  side  of  Hudson  Bay,  to  the  Mesnard 
quartzite  and  Kona  dolomite  of  the  lower  Huronian  of  the  Mar- 
quette district,  of  the  Lake  Superior  region.  He  also  reports  the 
discovery  of  certain  obscure  forms  possibly  representing  life  forms 
lower  than  the  Cambrian.  From  Low's  descriptions  and  photographs 
it  is  thought  that  the  iron-bearing  series  of  the  east  coast  of  Hudson 
Bay  corresponds  more  closety  to  the  Animikie  or  upper  Huronian  of 
the  Lake  Superior  region  than  to  the  lower  iron-bearing  series  of 
the  Lake  Superior  region.  In  various  areas  about  Hudson  Bay 
fragmental  rocks,  such  as  sandstone,  quartzite,  shale,  slate,  slate  con- 
glomerate, and  limestone,  occur.  These  are  associated  with  imperfect 
gneisses,  a  great  variety  of  schists,  and  schistose  and  jaspery  iron  ores. 
According  to  Bell,  above  these  rocks  at  Little  Whale  River  and  at 
Richmond  Gulf  are  formations  consisting  of  beds  of  siliceous  con- 
glomerate and  red  and  gray  sandstone,  with  some  red  shales.  Uncon- 
formably  overlying  this  intermediate  group  is  the  Manitounuck  grou]  >. 
which  consists  of  argillaceous  and  siliceous  limestones,  sandstones. 
quartzites,  shales,  amygdaloids,  basalts,  and  clay  ironstones.  On 
the  Coppermine  River  and  at  Doobaunt  Lake  occur  traps,  amygda- 
loids, and  porphyries,  associated  with  sandstones  and  conglomerates, 
constituting  a  scries  which  is  lithologically  similar  to  the  Keweena- 
wan  of  Lake  Superior. 
To  the  south  of  Hudson  Bay  the  preponderance  of  "  Laurentian  " 
rocks  is  the  same  as  elsewhere  in  this  region.  The  "  Huronian  "  rocks 
present  the  same  features  as  those  of  the  Lake  Superior  and  Union 
districts  to  the  south. 
