vanhise.]  EASTERN    ONTARIO    AND    WESTERN    QUEBEC.  33 
Iii  discussing  the  stratigraphical  succession,  large  areas  of  the  rocks, 
including  syenite,  granite,  porphyry,  etc.,  can  be  excluded,  for  it  is  cer- 
tain, as  was  early  recognized  by  Logan  and  Murray,  that  many  of  these 
rocks  are  eruptives  of  later  age  than  the  gneissic  and  schistose  rocks 
with  which  they  are  associated. 
Logan,  Murray,  and  Vennor  in  his  final  comprehensive  review,  reached 
the  same  stratigraphical  conclusions.  Occupying  the  inferior  position 
in  this  region  is  an  immense  thickness  of  syenitic,  granitic,  and  gneissic 
rocks.  For  the  most  part  this  lower  division  is  intricately  folded,  and  if 
it  has  a  stratigraphy,  ifc  is  of  so  complicated  a  character  that  no  esti- 
mate is  made  of  the  thickness.  Where  a  structure  is  present  there  is 
no  evidence  that  it  is  due  to  sedimentation.  It  contains  no  bedded 
limestones,  no  carbonaceous  schists,  no  elastics,  either  volcanic  or  water- 
deposited.  It  is,  then,  a  complex,  devoid  of  any  structure  which  has 
been  shown  to  be  bedding,  devoid  of  any  materials  which  may  not  be 
of  other  than  surface  origin.  As  described  by  Yennor,  this  lower  non- 
calcareous  Laurentian  covers  the  larger  part  of  the  region.  That  lime- 
stones were  at  one  time  supposed  to  be  contained  in  this  series  is  ex- 
plained by  him  to  be  due  to  the  fact  that  overlying  bands  of  the  upper 
division  are  included  as  infolded  troughs. 
Upon  these  rocks  rests  a  series  of  a  very  different  lithological  charac- 
ter. It  includes  great  thicknesses  of  limestones,  quartzites,  conglom- 
erates, hornblende-schists,  mica-schists,  and  bedded  gneisses.  If  the 
limestones,  quartzites  and  the  regularly  bedded  character  of  the  gneisses 
are  not  sufficient  evidence  of  a  clastic  origin,  the  presence  of  unmis- 
takable conglomerates  at  numerous  points  is  conclusive.  This  clastic 
series,  as  shown  by  the  descriptions  of  it  in  the  vicinity  of  Madoc,  is  in 
part  clearly  volcanic.  The  very  great  estimated  thickness  of  this  bed- 
ded series  may  be  questioned,  for  evidently  the  study  was  not  close 
enough  and  the  structure  well  enough  determined  to  decide  this  difficult 
question.  The  equivalence  of  the  clastic  rocks  of  the  different  districts 
has  been  assumed,  but  those  more  distant  from  the  type  area  differ  con- 
siderably from  it  in  lithological  character  as  well  as  from  each  other. 
That  they  are  really  equal  has  not  been  shown,  although  this  is  proba- 
ble for  certain  of  the  districts. 
As  to  the  anorthosite  series  it  may  be  excluded  from  'the  bedded 
succession.  It  is  now  believed  by  most  geologists  that  this  rock  is  an 
eruptive.  The  unconformity  at  its  base  is  an  eruptive  one,  in  all  prob- 
ability caused  by  the  outflowing  of  this  rock  at  a  later  period  than  the 
formation  of  the  underlying  series. 
The  Laurentian  clastic  series  of  the  type  area  resembles,  to  a  re- 
markable degree,  the  bedded  gneisses,  limestones,  graphitic  schists, 
and  quartzites  of  the  Adirondacks,  except  that  the  latter  have  become 
more  completely  crystalline.  The  core  of  the  Adirondacks  is  "  anor- 
thosite roek,"  really  gabbro,  and  away  from  this  the  bedded  series 
dips  in  a  quaquaversal  manner,  so  that  the  anorthosites  apparently 
Bull.  86 3 
