212  PRE-CAMBRIAN    ROCKS    OF    NORTH    AMERICA.  [bull.  86. 
diorites,  amygdaloids,  and  manganiferous  clay  ironstones.  The  lime- 
stones of  lake  Misstassini,  in  the  interior  of  the  Labrador  peninsula, 
bear  a  strong  resemblance  to  those  of  the  east  main  coast. 
Bell,9  in  1886,  gives  additional  observations  on  the  geology  of  Hud- 
son bay.  From  Eskimo  point  to  the  entrance  of  Chesterfield  inlet,  a 
distance  of  180  miles,  the  rock  specimens  embrace  hornblende-schists, 
greenstones,  sandstone  altered  to  quartzite  and  holding  fragments  of 
indurated  shale,  white  quartz  rock,  quartzite  like  that  of  Marble  island 
felsite,  crystalline  hornblende  rock,  diorite,  chert,  mica-schist,  porphyry, 
granulite,  red  jasper,  chloritic  schists,  etc.  The  majority  of  the  litho- 
logical  specimens  correspond  with  the  rocks  of  the  Huronian  series, 
Laurentian  types  are  absent,  and  the  probabilities  are  that  Huronian 
rocks  prevail  all  along  the  northwest  coast  of  Hudson  bay,  from  Eskimo 
point  to  Chesterfield  inlet,  and  again  at  Repulse  bay.  The  widely  ex- 
tended areas  of  massive  granitoid  character  about  Hudson  bay  are 
regarded  as  primitive  gneiss,  and  there  is  little  doubt  are  more  ancient 
than  the  regularly  stratified  gneisses  which  prevail  on  the  Ottawa  val- 
ley. The  Huronian  rocks  of  the  region  are  unlike  those  on  the  north 
shore  of  lake  Huron,  consisting  of  massive  diorites,  argillaceous  and 
dioritic  slate  conglomerates,  granite- syenites,  schistose  and  jaspery 
iron  ores,  limestones,  dolomites,  and  imperfect  gneisses,  with  a  great 
variety  of  schists.  The  Manitounuck  series  is  largely  made  up  of  rocks 
of  volcanic  origin. 
Bell,10  in  1887,  reports  on  explorations  of  portions  of  the  Attawa- 
pishkat  and  Albany  rivers.  Various  granites,  gneisses,  and  schists 
are  found  upon  Pelican  lake,  lake  St.  Joseph,  and  the  upper  sections 
of  Albany  and  Boulder  rivers,  and  lake  Lansdowne.  Upon  lake  St. 
Joseph  a  conglomerate  is  found.  The  granites  and  gneisses  are  placed 
with  the  Laurentian  and  the  schists  and  conglomerates  with  the  Hu- 
ronian. 
SUMMARY   OF   RESULTS. 
In  all  of  the,  above  works  by  Bell  the  rocks  are  classified  as  Lauren- 
tian or  Huronian  almost  wholly  upon  lithological  grounds,  the  coarse 
granites  and  granitoid  gneisses  being  regarded  as  Laurentian  and 
the  clearly  sedimentary  rocks  and  fine  grained  calcareous  gneisses 
and  various  green  schists  with  associated  rocks  being  placed  as  Hu- 
ronian. Whenever  the  relations  of  the  two  series  are  spoken  of  they 
are  said  to  be  in  conformity.  The  Huronian  is,  however,  frequently 
spoken  of  as  occurring  in  troughs,  which  probably  implies  that  this 
series  is  taken  to  be  the  newer  of  the  two ;  but  in  general  this  is  an 
inference  from  its  lithological  character  rather  than  a  determination 
from  an  ascending  succession.  The  dips  are  usually  high  and  no 
structure  is  worked  out,  so  that  from  the  facts  given  it  would  be  im- 
possible to  determine  which  is  higher  and  which  lower,  except  by  the 
implication  in  the  words  Huronian  and  Laurentian.    While  certain  of 
