23.4u  PKE-CAMBRIAN    ROCKS    OF    NOETH    AMERICA. 
[BULL.  8$ 
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  Carbonifer- 
ous are  destitute  of  granite  pebbles,  while  the  later  formations  abound 
in  them,  which  appears  to  indicate  that  the  granites  are  Devonian. 
Ells,42  in  1886,  finds  in  Albert  county  pre-Cambrian  rocks  which  in- 
clude 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  x>re-Cambrian  of  western  New 
Brunswick. 
Bailey,43  in  1890,  says  the  evidences  of  unconformity  between  the 
Primordial  and  Archean  are  clear,  varied,  and  widely  distributed.  It 
is  equally  evident  that  the  Archean  consists  of  two  groups  of  sediments,  j 
which  in  many  features  resemble  the  Laurentian  and  Huronian  sys-  j 
terns  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  proportional  amount  in  the  former  of 
distinctly  stratified  rocks,  such  as  slates  and  quartzites,  and  the  absence 
of  coarsely  crystalline  deposits.  As  regards  the  Huronian  rocks,  the 
greater  part  were  referred  to  as  felstones,  clay- stones,  porphyries,  and 
petrosilcx  before  the  introduction  of  the  present  methods  of  petrograph- 
ical  research  and  their  names  in  some  instances  are  probably  misapplied. 
The  relations  of  the  Laurentian  and  Huronian  systems  are  not  well 
understood.  While  the  author  does  not  doubt  that  the  clastic  and 
schistose  rocks  referred  to  the  Huronian  are  more  recent  than  the  grani- 
toid gneissic  and  crystalline  limestones  regarded  as  Laurentian,  a  con- 
trary view  has  been  taken  by  others. 
Matthew,44  in  1890,  states  that  in  the  upper  Laurentian  of  New 
Brunswick  fossils  occur  at  three  horizons.  The  oldest  of  these  is  in  a 
quartzite  in  the  lower  half  of  the  system.  This  contains  Hexactinellid 
sponges,  allied  to  the  genus  Cyathospongia.  The  second  horizon  is  in  the 
upper  limestone.  It  contains  calcareous  coral  like  structures  which 
bear  a  resemblance  to  Stromatopora  rugosa.  The  third  horizon  is  that 
of  the  graphite  beds,  in  which  occurs  great  numbers  of  sponge  spicules, 
arranged  in  parallel  sets,  one  set  crossing  the  other  at  an  acute  angle. 
The  type  of  sponge  is  apparently  Monactinellid.  Eozoon  also  occurs  in 
the  Laurentian.  Between  the  upper  Laurentian  system  and  the  basal 
Cambrian  occurs  a  third  system  of  rocks,  the  Coldbrook  and  Coastal, 
which  has  given  conglomerates  to  the  Cambrian  and  has  a  great  thick- 
ness. 
SUMMARY   OF   RESULTS. 
While  the  mapping  of  the  province  of  New  Brunswick  has  been  com- 
pleted by  the  official  survey,  the  statements  of  the  later  papers  of  those 
who  have  taken  the  most  active  part  in  this  mapping  make  it  certain 
