vanhisb.]  EASTERN    ONTARIO    AND    WESTERN    QUEBEC.  29 
deposits  of  iron  ore.  Eozoon  canadense  occurs  in  the  topmost  member 
of  the  upper  division  (G).  Division  B  rests  immediately  upon  A,  but 
whether  conformably  or  not  is  not  determined,  as  the  basal  members  of 
B  are  massive  diorites  and  greenstones. 
Vennor,20  in  1872,  applies  to  the  lowest  division  of  the  Hastings 
series  (A),  the  term  Lauren tian,  and  the  middle  division  (B)  is  placed 
as  probable  Huronian.  The  rocks  of  the  upper  group  are  found  to  lie 
unconformably  upon  the  gneisses  and  crystalline  limestones  of  the  low- 
est, and  it  is  probable  that  the  middle  group  is  unconformably  below 
the  upper  and  unconformably  above  the  lower  group. 
Vennor,21  in  1872,  reports  on  Leeds,  Frontenac,  and  Lanark  counties, 
Ontario.  The  granite  of  the  gold-bearing  rocks  is  believed  to  repre- 
sent eruptions  which  took  place  probably  toward  the  close  of  the  Lau- 
ren tian  period,  or  at  some  time  prior  to  the  deposition  of  the  rocks  of 
divisions  B  and  0,  for,  whenever  these  higher  rocks  are  wanting,  the 
Laurentian  gneisses,  quartzites,  and  limestone  are  cut  by  a  network  of 
veius. 
Vennor,22  in  1873,  gives  an  additional  report  upon  the  counties  of 
Frontenac,  Leeds,  and  Lanark.  The  area  is  divided  into  western,  mid- 
dle, and  eastern  sections.  In  the  western  section  the  main  mass  of 
rocks  is  of  granite,  syenite,  and  coarse  and  fine  grained  gneisses.  The 
red  granites  sometimes  appear  to  be  of  later  date  than  the  white  mica- 
granites  and  even  of  the  diorites  of  division  B.  Limestone  was  not  ob- 
served. In  a  trough  between  two  granite  and  gneiss  areas  are  found 
diorite-slates,  micaceous  and  chloritic  schists,  pyroxenic  rocks,  con- 
glomerates, dolomites,  and  sandy  crystalline  limestones.  In  one  con- 
glomerate the  pebbles  of  quartz  in  a  matrix  of  sand  and  mica  are  flat- 
tened out  along  the  plane  of  bedding,  so  that  those  which  in  cross 
measurement  are  not  more  than  one-fifth  of  an  inch  broad  have  a  length 
of  from  5  to  10  inches.  In  places  in  the  conglomerate,  instead  of  peb- 
bles, are  layers  of  vitreous  quartz  or  quartzite  and  mica-schist.  The 
middle  section  is  undoubtedly  Lower  Laurentian.  The  rocks  met  with 
include  great  thicknesses  of  gneiss,  for  the  most  part  clearly  stratified, 
with  well  denned  strike  and  dip;  masses  of  hornblende  rock  and  diorite, 
graduating  into  slate  or  schist;  large  and  important  bands  of  crystal- 
line limestones,  and  groups  of  calcareous  strata  associated  with  mica- 
slates,  and  Avorkable  masses  of  magnetic  iron  ore.  These  rocks  are 
clearly  interstratined.  Apparently  five  distinct  bands  of  crystalline 
limestone  are  met  with,  separated  by  reddish  granitic  and  dark  horn- 
blendic  gneisses.  The  rocks  of  the  eastern  section  consist  chiefly  of 
gneiss,  but  associated  with  this  are  coarsely  granular  limestones.  The 
horizontal  limestones  of  the  Lower  Silurian  by  a  fault  are  brought  into 
abrupt  vertical  contact  with  the  Laurentian  gneiss. 
Vennor,23  in  1874,  further  describes  Frontenac,  Leeds,  and  Lanark 
counties.  The  five  belts  of  crystalline  limestones  mentioned  in  the  pre- 
vious report  are  described  in  detail.  Eozoon  occurs  abundantly  in 
places. 
