496  pketCambpjan  geology  of  north  America. 
and  northern  portions  of  the  province.  In  the  rocks  referred  to  the 
Huronian  are  two  well-marked  divisions,  the  lower  or  Coldbrook 
group  and  the  upper  or  Coastal  group,  between  which  there  is  not 
infrequently  evidence  of  at  least  a  partial  unconformity.  The  pre- 
Silurian  rocks  are  of  vast  thickness;  their  divisions  were  deposited 
under  markedly  different  conditions;  there  are  unconformities  be- 
tween these  divisions.  These  facts  show  that  these  rocks  are  at  least 
as  old  as  the  Huronian  and  portions  of  the  Laurentian  system. 
Above  the  Upper  Silurian  rocks  are  found  felsite  porphyries  and 
peculiar  orthoplryres  at  Passamaquoddy  Bay  and  at  Eastport  and 
Pembroke,  Me.  On  St.  John  River,  associated  with  the  fossiliferous 
rocks  are  amygdaloidal  and  ash  rocks  which  are  indistinguishable 
lithologically  from  the  Huronian  formation,  to  which  all  of  these 
rocks  have  previously  been  referred. 
Bailey,22  in  1885,  finds  the  granites  of  southern  and  Central  New 
Brunswick  to  be  of  intrusive  character  and  to  cut  rocks  as  late  in  age 
as  the  Carboniferous.  As  evidence  of  this  are  cited  the  abrupt  transi- 
tions from  the  massive  granite  to  the  associated  schists;  the  wTidelv 
different  characters  of  the  invaded  beds;  the  fact  that  foliation  and 
crystallization  are  most  marked  in  the  vicinity  of  the  granite  and 
decrease  with  increase  of  distance  from  it;  the  outlines  of  the  granite 
are  irregular  and  are  in  some  places  parallel  with,  in  other  places 
oblique  to,  and  in  still  others  at  right  angles  to,  the  foliation  of  the 
rocks  cut ;  detached  masses  or  bosses  of  granite  border  main  granitic 
areas;  granite  veins  like  those  of  the  main  mass  of  granite  penetrate 
the  schists  in  all  directions  adjacent  to  the  granite  masses;  large 
detached  blocks  of  schists  and  gneiss,  usually  angular,  are  frequently 
contained  in  the  granite,  sometimes  being  so  abundant  as  to  produce 
the  appearance  of  a  coarse  breccia.  As  to  the  age  of  these  granites,  no 
veins  are  found  penetrating  later  strata  than  the  Upper  Silurian,  but 
all  conglomerates  older  than  the  Lower  Carboniferous  are  destitute 
of  granite  pebbles,  while  the  later  formations  abound  in  them,  which 
appears  to  indicate  that  the  granites  are  Devonian. 
Ells,23  in  1886,  finds  in  Albert  County  pre-Cambrian  rocks  which 
include  quartzite,  felsite,  gneiss,  syenite,  and  granite.  The  crystalline 
limestone  rests  generally  upon  the  flanks  of  the  schistose  series.  These 
rocks  are  an  eastern  extension  of  the  pre-Cambrian  of  western  New 
Brunswick. 
Bailey,24  in  1890,  says  that  the  evidences  of  unconformity  between 
the  Primordial  and  the  Archean  are  clear,  varied,  and  widely 
distributed.  It  is  equally  evident  that  the  Archean  consists  of  two 
groups  of  sediments,  which  in  many  features  resemble  the  Laurentian 
and  Huronian  systems  of  Canada;  but  there  are  equally  striking 
differences  between  the  supposed  Laurentian  rocks  of  St.  John  and 
those  of  Canada,     This  is  especially  marked  by  the  greater  propor- 
