QUEBEC    NORTH    AND    WEST    OF    ST.    LAWRENCE    RIVER.  469 
Barlow,42  in  1897,  gives  a  further  account  of  the  results  of  work 
being  carried  on  by  himself  and  Adams  in  the  counties  of  Hastings, 
Haliburton,  and  Renfrew,  Province  of  Ontario.  Many  of  the  so- 
called  conglomerates  of  the  Hastings  and  Grenville  series  are  believed 
to  be  autoclastic  rocks  or  pseudoconglomerates  which  have  resulted  in 
the  main  from  complex  folding  and  stretching.  Therefore  such  rocks 
can  not  be  cited  as  evidence  of  the  clastic  origin  of  the  Hastings  and 
Grenville  series,  as  has  been  done. 
Adams  and  Barlow,43  in  1897,  give  a  general  outline  of  geological 
work  begun,  but  not  yet  finished,  in  the  Laurentian  of  central  Ontario, 
in  the  area  of  map  sheets  No.  118  and  a  portion  of  119  of  the  Ontario 
series  of  geological  maps,  and  indicate  certain  conclusions  which 
seem  likely  to  be  reached  concerning  the  origin  and  relations  of  the 
Grenville  and  Hastings  series. 
The  Fundamental  gneiss  occupies  the  northwestern,  by  far  the 
larger,  portion  of  the  area.  It  consists  of  igneous  rocks  closely 
allied  to  granites,  diorites,  and  gabbros,  all  showing  more  or  less 
distinct  foliation. 
The  Grenville  and  Hastings  series  are  principally  exposed  in  the 
southeastern  portion  of  the  area,  the  Grenville  series  appearing  in  a 
belt  adjacent  to  the  Fundamental  gneiss,  and  between  the  Funda- 
mental gneiss  and  the  Hastings  series. 
The  Grenville  series  is  composed  principally  of  gneisses  identical 
in  character  with  the  Fundamental  gneiss,  but  it  contains  also,  and  is 
characterized  by,  a  small  quantity  of  altered  sediments,  chiefly  lime- 
stone. Some  varieties  of  the  gneissic  rocks  may  owe  their  origin  to 
the  partial  commingling  of  the  sedimentary  material  with  the  igneous 
rocks  by  actual  fusion.  The  strike  of  the  foliation  of  the  rocks  of  the 
series  follows,  in  a  general  way,  that  of  the  Fundamental  gneiss.  The 
Grenville  series  is  believed  to  be  a  sedimentary  series,  later  than  the 
Fundamental  gneiss,  which  has  sunk  down  into,  and  been  invaded  by, 
intrusions  of  the  latter  series  when  this  was  in  a  semimolten  or  plastic 
condition. 
The  Hastings  series  is  composed  chiefly  of  thinly  bedded  limestones. 
dolomites,  etc.,  cut  through  by  great  intrusions  of  gabbro,  diorite, 
and  granite.  This  series  is  believed  to  represent  the  Grenville  series 
in  a  less  altered  form.  That  is,  the  Fundamental  gneiss,  upon  which 
the  Hastings  series  was  originally  laid  down,  having  at  a  subsequent 
time  been  softened  by  the  influence  of  heat,  and  having  under  the 
influence  of  dynamic  action  eaten  into  and  fretted  away  the  overlying 
Hastings  series,  gave  rise  to  an  intermediate  zone  of  mixed  rocks 
which  constitutes  the  Grenville  series.  The  Grenville  series  may. 
however,  represent  only  a  portion  of  the  Hastings  series,  and  the  work 
so  far  done  has  been  insufficient  to  determine  the  stratigraphical  posi- 
