EASTERN    TOWNSHIPS   OF   QUEBEC.  485 
Selwyn,5  in  1883,  in  speaking  further  of  the  Quebec  group,  asserts 
of  the  upper  metamorphic  or  volcanic  group  that  neither  a  schistose 
nor  a  bedded  structure  can  be  accepted  as  proof  of  nonigneous  origin, 
and  that  a  massive  lava  flow  is  as  likely,  through  pressure  and  meta- 
morphism,  to  assume  a  schistose  structure  as  are  ordinary  sedimentary 
strata.  Much  of  the  material  of  the  upper  part  of  the  lower  groups 
is  of  contemporaneous  irruptive  and  eruptive  origin,  though  for  the 
most  part,  through  cleavage  and  alteration,  so  changed  in  external 
and  physical  character  as  to  cause  these  rocks  to  be  classed  as  meta- 
morphic, notwithstanding  that  they  still  closely  correspond  in  chem- 
ical composition  with  recognized  igneous  and  volcanic  rocks,  and 
differ  essentially  from  any  known  ordinary  unmixed  sedimentary 
deposits.  It  is  suggested  that  the  upper  volcanic  group  may  represent 
the  Keweenian. 
Ells,6  in  1887,  reports  on  the  geology  of  a  portion  of  the  Eastern 
Townships.  Placed  in  the  Cambrian  are  a  set  of  slates  of  various 
colors,  sandstones  passing  into  quartzites,  quartziferous  schists,  and 
conglomerates  in  which  are  found  no  calcareous  beds  or  fossils.  The 
conglomerates  are  of  two  kinds;  one  is  composed  of  pebbles  of  the 
ordinary  kind — granitoid  rocks,  quartzites,  slates,  etc. ;  the  other 
is  composed  largely  of  dioritic  pebbles  in  a  diorite  paste,  with  inter- 
calated beds  of  sandstones  and  grits,  and  may  be  regarded  as  an  ag- 
glomerate. This  series  in  places  is  certainly  unconformable  to  the 
Cambro- Silurian  system  on  the  one  hand,  and  on  the  other  to  the 
underlying  ridges  of  crystalline  rocks  from  the  debris  of  which  they 
are  largely  formed.  These  strata  for  the  most  part  flank  the  ridges 
of  crystalline  schists  and  gneisses,  but  at  other  times  are  in  intricately 
folded  basins  in  them.  These  rocks  resemble  the  gold-bearing  series 
of  Nova  Scotia.  When  near  to  or  cut  by  masses  of  granite  the  strata 
have  developed  in  them  crystals  of  chiastolite  and  staurolite. 
The  areas  of  crystalline  schists,  gneisses,  and  limestones,  with  ser- 
pentines and  associated  strata,  are  referred  to  the  pre-Cambrian. 
The  age  of  these  rocks  is  inferred  from  their  lithological  character, 
from  their  position  of  apparent  unconformity  below  the  overlying 
series  referred  to  the  Cambrian,  and  from  the  fact  that  their  debris 
is  found  in  the  latter  series.  The  areas  of  pre-Cambrian  rocks  are 
four  in  number.  In  position  and  in  the  fact  that  they  contain  copper 
they  closely  resemble  the  copper-bearing  rocks  of  New  Brunswick  and 
the  Huronian  of  the  Bruce  mines.  There  is  a  similarity  to  the  series 
in  England  and  Scotland  described  by  Hicks  under  the  names  of 
Dimetian,  Arvonian,  and  Pebidian.  Summing  up  it  is  said:  What- 
ever may  be  the  exact  age  of  these  altered  rocks,  their  present  aspect 
entitles  them  to  be  classed  as  very  ancient  sediments,  nit  hough,  in 
view  of  the  great  alterations  which  may  result  from  intense  regional 
metamorphism,  there  is  no  reason  why  many  of  the  ordinary  sedimen- 
