536  PRE-CAMBRIAN   GEOLOGY   OF   NORTH   AMERICA. 
weenaw  or  Animikie  of  the  Lake  Superior  region,  and  probably  rep- 
resent both  groups  of  that  great  copper-bearing  series.  Throughout 
the  northern  part  of  the  continent  the  characteristic  Cambrian  forma- 
tion, composed  largely  of  volcanic  rocks,  apparently  occupies  an  un- 
conformable position  with  regard  to  the  underlying  Laurentian  and 
Huronian  systems.  The  present  remnants  show  that  these  rocks  have 
undergone  comparatively  little  subsequent  disturbance.  The  Cape 
Rawson  beds  of  Grinnell  Land  are  provisionally  referred  to  the  Cam- 
brian, on  account  of  their  lithological  resemblance  to  the  rocks  of 
the  Animikie,  and  also  on  account  of  their  similarity  to  the  Nova 
Scotia  gold-bearing  series. 
In  the  above  summary,  as  the  terms  are  used  in  this  volume  by  Daw- 
son, the  Middle  Laurentian,  much  of  the  Huronian,  and  the  Copper- 
mine and  equivalent  series,  which  are  placed  in  the  Cambrian,  are 
to  be  included  in  the  Algonkian;  while  the  Lower  Laurentian  is 
largely  or  wholly  Archean. 
Packard,45  in  1888,  describes  syenitic  and  gneissic  rocks  of  the 
Laurentian  formation  at  various  points,  among  which  are  Sleupe 
Harbor  in  Gore  Island  near  Shallop,  the  bay  east  of  Anse-au-Loup, 
Caribou  Island,  Cape  St.  Francis,  and  Square  Island. 
McConnell,40  in  1890,  mentions  granite  gneisses  east  of  the  Rocky 
Mountains  at  the  rapids  of  Slave  River  and  Fort  Rae.  These  evi- 
dently belong  to  the  Laurentian  or  the  oldest  division  of  the  Archean. 
West  of  the  Rocky  Mountains  crystalline  schists  are  largely  developed 
along  the  valley  of  the  Pelly- Yukon,  occurring  in  numerous  ex- 
posures from  the  international  boundary  to  Fort  Selkirk,  and  they 
continue  up  the  Lewes  about  30  miles.  This  belt  of  crystalline  rocks 
has  a  width  of  somewhat  more  than  a  hundred  miles.  The  eastern 
edge  of  the  area  consists  largely  of  quartzose  schists,  chlorite  schists, 
mica  schists,  diabases,  and  serpentines,  which  are  occasionally  inter- 
bedded  with  bands  of  slate  and  limestone,  and  are  broken  in  many 
places  by  igneous  intrusions.  The  green  schists,  in  ascending  the 
river,  are  underlain  by  foliated  mica  gneisses  alternating  with  horn- 
blende gneisses,  which  are  distinctly  Archean  in  appearance  and  in 
lithological  character. 
McConnell,47  in  1893,  reports  a  small  area  of  Archean  gneisses  on 
the  northern  shore  and  neighboring  islands  of  Lake  Athabasca,  on 
the  islands  of  Lake  Mammawi,  and  in  the  tilted  deposits  bordering 
Quatre  Fourches  River.  The  gneisses  include  hornblendic,  mica- 
ceous, chloritic,  and  epidotic  varieties.  In  places  they  pass  into  a 
mica  schist  or  chlorite  schist.     The  gneisses  strike  N.  10°  to  20°  W. 
Dowling,48  in  1896,  reports  on  the  geology  of  the  country  in  the 
vicinity  of  Red  Lake  and  part  of  the  basin  of  Berens  River,  in  the 
district  of  Keewatin,  Canada.     The  rocks  exposed  are  all  Archean, 
