500  PRE-CAMBBIAN    GEOLOGY   OF    NORTH   AMERICA. 
portions  of  the  shore  of  the  Bay  of  Fundy  between  Beaver  Harbor 
and  Point  Lepreau,  where,  at  different  places,  through  the  agency 
of  intrusives,  the  ordinary  sedimentary  rocks  of  Silurian  and  Devo- 
nian age  had  become  altered  to  the  condition  of  schists  of  pre-Cam- 
brian  aspect. 
Ells,34  in  1906,  summarizes  some  of  the  problems  in  New  Bruns- 
wick geology. 
NORTHERN    AND    CENTRAL    NEW    BRUNSWICK. 
Robb,35  in  1870,  gives  a  report  on  the  geology  of  central  New  Bruns- 
wick. The  crystalline  rocks  include  (1)  a  band  of  metamorphic  rocks 
immediately  underlying  the  Carboniferous  series  and  extending  to 
the  southeastern  boundary  of  the  great  granite  area,  (2)  the  central 
granite  area,  and  (3)  a  band  of  noncalcareous  metamorphic  slate  and 
quartzite  lying  immediately  northwest  of  the  granite  area.  The 
southern  slate  band  extends  from  Magaguadavic  Lake  to  the  south- 
west Miramichi,  its  breadth  varying  from  9J  miles  on  St.  John  River 
to  17  miles  on  the  Miramichi.  The  rocks  consist  of  argillaceous  and 
micaceous  clay  slates,  with  interposed  bands  of  crystalline,  quartzose, 
micaceous,  and  feldspathic  rocks  resembling  sandstone.  They  are 
doubtless  altered  sediments.  In  one  place  apparently  in  this  series 
are  fossils,  probably  of  Upper  Silurian  or  Devonian  age.  The  central 
granite  occupies  a  considerable  area  to  the  northwest  of  the  slates. 
The  line  between  the  slates  and  the  granite  is  somewhat  arbitrary, 
for  the  slate  and  quartzite  band  includes  three  very  considerable, 
with  some  smaller,  bands  of  granite.  The  various  feldspathic  rocks 
of  the  region  seem  to  merge  into  one  another.  This  is  true  not  only 
of  the  granite  and  gneiss  but  even  of  the  foliated  semicrystalline 
slates  and  quartzites.  Occasionally  fragments  of  gneiss  of  all  shapes 
and  sizes  are  found  embedded  or  incorporated  in  the  granite,  and  vice 
versa;  but  no  appearance  of  granite  veins  cutting  the  laminated  rocks 
is  noted.  The  slates,  mica  schists,  and  quartzites  of  the  northern 
slate  belt  locally  assume  a  crystalline  aspect.  Bands  of  crystalline 
rocks  resembling  granite,  syenite,  and  diorite  are  intercalated  in  the 
manner  of  conformable  or  interbedded  masses.  At  one  place  is  found 
a  slate  conglomerate,  which  is  believed  to  occupy  a  depression  in  the 
older  rocks. 
Robb,36  in  1872,  gives  some  additional  facts  in  continuation  of  his 
studies.  The  central  granite  area  is  divided  into  two  granitic  bands. 
Much  of  the  granite  area  is  of  a  gneissoid  character.  Where  the 
change  from  granite  to  slate  occurs  the  granite  near  the  line  of  contact 
is  often  of  a  red  variety  and  rather  fine  grained,  gradually  passing 
into  the  ordinary  color  and  texture  in  receding  from  the  line.  All 
attempts  to  elucidate  the  structural  relations  of  the  granite  have 
proved  futile.     In  the  slate  band  northwest  of  the  granite  are  con- 
