van  hise.J  EASTERN    CANADA    AND    NEWFOUNDLAND.  225 
constitutes  the  lowest  of  all  the  geological  formations  encountered  in 
this  portion  of  the  province. 
Both  plntonic  and  volcanic  rocks  occur  in  the  Eastern  Townships,  in- 
cluding granites  and  diorites,  some  of  which  are  at  least  as  late  in  age 
as  the  Lower  Silurian,  although  others  are  earlier,  as  is  shown  by  the 
fact  that  fragments  of  them  are  included  in  the  strata  referred  to  the 
Cambrian.  The  sedimentary  strata  are  altered  at  the  contacts  with 
these  intrusives.  These  granites  are,  however,  held  by  Selwyn  to  be 
metamorphic. 
Selwyn,7  in  1887,  states  that  at  the  Bras  stream,  about  3  miles  from 
the  Chaudiere  river,  is  well  exposed  a  contact  of  the  crystalline  series 
with  the  black  slates,  showing  the  same  unconformable  relations 
between  the  Cambrian  and  pre-Cambrian  as  on  the  Quebec  Central 
railway.  The  granites  considered  by  Ells  as  intrusive  are  regarded  as 
more  probably  formed  in  situ  by  the  same  metamorphic  agencies  that 
have  altered  the  adjacent  strata,  and  the  so-called  dikes  are  probably 
due  to  segregation;  in  fact,  the  latter  are  rather  veins  than  dikes. 
The  granites  are  then  regarded  as  an  effect  of  the  metamorphosing 
agencies  rather  than  the  cause  of  the  metamorphism. 
Ells,8  in  1880,  gives  a  second  report  on  the  geology  of  the  Quebec 
group.  Throughout  the  area  of  the  rocks  referred  to  the  Lower  Cam- 
brian no  fossils  have  yet  been  found,  but  they  resemble  the  lower  por- 
tion of  the  Cambrian  of  New  Brunswick.  The  most  that  can  be  said  of 
them  stratigraphically  is  that  they  are  intermediate  between  the  chlo- 
ritic  and  micaceous  schists  of  the  central  anticlinal  and  the  overlying 
rocks  of  the  Sillery.  These  Cambrian  rocks  have  certain  beds  which 
closely  resemble  those. of  the  Potsdam  age  of  the  Sillery;  on  the  other 
hand,  it  is  not  easy  to  separate  them  from  the  underlying  pre-Cambrian 
schists,  although  at  certain  points  there  is  a  manifest  unconformity 
between  the  two  series,  as  is  well  shown  between  Broughton  station 
and  Harvey  hill  on  the  Quebec  Central  railway;  the  regular  strike  of 
the  underlying  chloritic  rocks  being  nearly  east  and  west,  while  the 
overlying  black  slate,  with  which  are  associated  beds  of  grayish  lime- 
stone, at  times  strike  nearly  north  and  south.  The  difference  in  the 
character  of  the  Cambrian  and  pre-Cambrian  strata,  together  with  the 
fact  of  the  occurrence  of  a  line  of  fault  between  the  crystalline  schists 
of  the  Sutton  mountain  anticlinal  and  the  slates  and  serpentines  to  the 
east,  are  the  chief  reasons  for  the  separation  of  these  two  series  into  pre- 
Cambrian  and  Cambrian.  The  pre-Cambrian  areas  found  are  com- 
posed mostly  of  alternations  of  chloritic  and  micaceous  schists,  in 
certain  localities,  as  at  Les  Saints  Anges,  are  found  micaceous  black 
and  gray  slates,  and  quartzites  with  crystalline  limestone,  which  may 
be  Cambrian  or  pre-Cambrian.  The  areas  of  granite,  diorite,  and  ser- 
pentine are  described. 
Adams,9  in  1889,  iinds  that  the  massive  and  stratified  varieties  of 
the  anorthosite  underlying  the  northwest  part  of  the  Eastern  Townships 
Bull.  86 15  * 
