EASTERN    TOWNSHIPS   OF   QUEBEC.  487 
may  be  Cambrian  or  pre-Cambrian.  The  areas  of  granite,  diorite, 
and  serpentine  are  described. 
Ells,9  in  1890,  states  that  the  lowest  beds  of  the  Lower  Cambrian 
contain  in  many  places  a  very  considerable  thickness  of  conglom- 
erates, the  pebbles  of  which  are  without  doubt  derived  from  the  under- 
lying crystalline  ridges  which  have  been  called  pre-Cambrian.  They 
are  distinct  in  character  from  the  pre-Cambrian  of  the  anticlines, 
the  latter  being  in  all  cases  highly  crystalline,  while  there  is  a  sharply 
defined  line,  either  of  unconformable  overlap  or  of  fault,  between  the 
crystalline  series  and  the  slates  and  quartzites  of  what  has  been  styled 
Lower  Cambrian.  This  line  of  fault  is  to  be  seen  at  certain  points, 
and  is  heavy ;  at  others  the  slates  occupy  basin-like  areas  infolded  in 
the  schists,  where  the  rocks  pass  at  once  from  the  black,  gray,  and 
purple  slates  to  the  highly  altered  schists.  There  are  certain  areas  of 
mica  schists  and  black  slates  which  are  apparently  in  the  center  of  the 
anticline  of  Sutton  or  the  Chaudiere.  These  probably  represent  a 
portion  of  the  pre-Cambrian,  but  they  are  quite  distinct  from  the  or- 
dinary black,  purple,  and  gray  slates  and  quartzites  of  the  Chaudiere 
gold  series. 
Ells,10  in  1896,  reports  on  the  geology  of  a  portion  of  the  Province 
of  Quebec  comprised  in  the  area  covered  by  the  southwest  sheet  of  the 
Eastern  Townships  map  (Montreal  sheet),  and  describes  pre-Cam- 
brian rocks  occurring  to  the  east  of  St.  Lawrence  River.  These  occur 
along  the  axis  of  the  Sutton  Mountain  range  and  in  the  anticline 
east  of  Memphremagog  Lake  near  Fitch  Bay. 
The  crystalline  schists  of  the  Sutton  Mountain  range  may  be  di- 
vided into  two  principal  portions,  (1)  the  gneissic,  micaceous,  quartz- 
ose,  and  talcose  schists  of  the  central  portion,  or  that  in  which  the 
axis  of  the  anticline  is  situated,  and  (2)  a  series  of  green,  chloritic, 
schistose  rocks,  with  the  characters  of  altered  dioritic  rocks,  consti- 
tuting an  easily  separable  portion,  flanking  the  central  area  of  schists 
to  the  west  and  extending  from  the  Vermont  boundary  to  the  St. 
'Francis  in  the  vicinity  of  Richmond.  This  second  or  chloritic  divi- 
sion is  recognized  also  at  various  points  on  the  eastern  slope  of  the 
range,  but  it  does  not  there  present  so  marked  a  development.  The 
age  of  the  green  schistose  dioritic  portion  is  doubtful,  but  it  appears 
to  coincide  to  some  extent  with  the  Volcanic  group  of  Selwyn,"  which 
he  supposed  to  be  probably  Lower  Cambrian  or  Huronian. 
East  of  Memphremagog  Lake,  near  Fitch  Bay,  the  pre-Cambrian 
rocks  are  schistose,  altered,  dioritic  rocks,  occasionally  with  micaceous 
bands,  and  often  containing  clear  grains  of  quartz.  These  rocks  are 
apparently  allied  to  the  green  chloritic  schists  of  the  wesl   -lope  of 
a  Selwyn,  A.  R.  C,  Stratigraphy  of  the  Quebec  group  and  the  older  crystalline  rocks  of 
Canada:    Kept.  Geol.  Survey  Canada,   1N77-7S,  pi.  a,  p.  .'!. 
