230  PRE-CAMBRIAN    ROCKS    OF    NORTH    AMERICA.  I  bull.  86. 
SECTION  IV.       SOUTHERN  NEW  BRUNSWICK. 
LITERATURE. 
Gesner,20  in  1839,  gives  many  details  as  to  particular  localities  in 
southern  New  Brunswick.  The  succession  of  rocks  below  the  Old  Red 
sandstone  is  argillaceous  slate  and  granite.  The  volcanic  rocks  of  the 
bay  of  Fundy  are  of  different  ages. 
Gesner,21  in  1840,  gives  a  continuation  of  his  study  of  the  previous 
year. 
Gesner/22  in  1841,  describes  the  geology  of  the  county  of  St.  John 
more  fully  than  in  rjrevious  reports.  The  syenites  occupy  a  large  area, 
and  against  these  lean  the  slates,  graywackes,  and  limestones  parallel 
to  the  coast  of  the  bay  of  Fundy,  but  there  is  a  group  of  more  schistose 
rocks  containing  no  organic  remains  which  dip  toward  this  ridge. 
These  "latter  are  evidently  primary,  while  the  graywackes  and  gray- 
wacke-slates  are  Cambrian  or  Silurian.  It  is  certain  that  a  part  of  the 
granitic  and  syenitic  rocks  which  have  been  regarded  as  primary  really 
belong  to  a  later  age. 
Gesner,23  in  1842,  finds  that  the  graywackes  and  slates  provisionally 
correlated  with  the  Cambrian  were  deposited  prior  to  the  elevation  of 
the  granitic,  syenitic,  and  trappean  masses  upon  which  they  rest,  as 
they  are  fractured  in  all  directions  by  dikes  and  extensive  elevations 
of  those  rocks. 
Gesner,24  1843,  places  the  granite,  syenite,  trap,  and  serpentine  in 
the  unstratified  rocks.  To  the  Cambrian  system  are  referred  a  series 
of  graywackes  and  clay-slates  which  are  sometimes  conglomeratic. 
These  rocks  extend  from  the  American  boundary  to  near  Bathurst, 
and  in  them  organic  remains  occur. 
Johnston,25  in  1850,  in  a  report  on  the  province  of  New  Brunswick, 
gives  a  map  by  Robb  in  which  the  crystalline  rocks  are  outlined  as 
granite,  gneiss  and  mica-slate,  and  trap  rocks. 
Bailey,  Matthew  and  Hartt,26  in  1865,  in  observations  on  the  geo- 
logy of  southern  New  Brunswick,  give  a  resume  of  the  work  previously 
done.     Of  the  15  different  groups  of  rocks,  the  lowest  consists  prinejl 
pally  of  granite,  gneiss,  mica-schist,  and  thick  beds  of  crystalline  lime- 
stone.   This  is  the  Lauren tian  or  Portland  group.    Resting  upon  the 
Portland  group  is  the  Coldbrook   group,   belonging  to  the   Huronian  • 
division  of  the  Azoic  system,  and  thick  deposits  of  altered  slate  of  aJ 
volcanic  character,   surmounted    by  conglomerates.    The  Coldbrook^ 
group  is  succeeded  by  the  St.  John  group,  which  contains  no  coarse 
material  and  is  regarded  as  equivalent  to  the  Potsdam  or  Primordial 
of  New  York.     Above  the  St.  John  group  is  the  Bloomsbury  group  of 
volcanic  character,  such  as  basalt,  amygdaloid,  and  trap  rock,  which 
are  associated  with  conglomerates  and  slates  destitute  of  fossils.    Geo- 
graphically  separated  from  the  above  groups  are  the  rocks  of  Kingston, 
which  are  regarded  as  Upper  Silurian,  and  the  mica-schists  of  Queens 
