﻿328 
  H. 
  L. 
  Smyth 
  — 
  Geology 
  of 
  Steep 
  Rook 
  ZaJce, 
  Ont. 
  

  

  lamination 
  of 
  the 
  sediments 
  and 
  banded 
  schists 
  of 
  the 
  Steep 
  

   Rock 
  Series, 
  and 
  is 
  now 
  the 
  dominant 
  structure. 
  

  

  In 
  inferring 
  the 
  orotechnic 
  history 
  of 
  the 
  region 
  the 
  origin 
  

   of 
  the 
  N.E. 
  cleavage 
  must 
  be 
  ascribed 
  to 
  a 
  force 
  acting 
  per- 
  

   pendicular 
  to 
  it, 
  or 
  in 
  a 
  N.W. 
  and 
  S.E. 
  direction 
  ; 
  and 
  since 
  

   this 
  cleavage 
  runs 
  through, 
  and 
  in 
  many 
  cases 
  masks 
  all 
  pre- 
  

   vious 
  structure, 
  the 
  force 
  which 
  produced 
  it 
  must 
  have 
  been 
  

   the 
  last 
  force 
  which 
  has 
  left 
  its 
  marks 
  upon 
  the 
  rocks 
  of 
  the 
  

   lake. 
  To 
  this 
  force 
  also 
  must 
  be 
  ascribed 
  the 
  action 
  which 
  

   left 
  the 
  Steep 
  Rock 
  series 
  in 
  its 
  present 
  folded 
  attitude. 
  

  

  What 
  was 
  the 
  position 
  of 
  the 
  rocks 
  just 
  before 
  this 
  cleavage- 
  

   producing 
  force 
  acted 
  upon 
  them 
  ? 
  It 
  could 
  not 
  have 
  been 
  

   horizontal, 
  for 
  in 
  the 
  long 
  stretch 
  in 
  East 
  Bay, 
  where 
  the 
  

   strike 
  runs 
  nearly 
  straight 
  for 
  four 
  miles, 
  and 
  in 
  the 
  limestone 
  

   exposures 
  N.W. 
  of 
  the 
  Elbow, 
  the 
  plane 
  of 
  the 
  dip 
  nearly 
  

   coincides 
  with 
  the 
  direction 
  of 
  this 
  force, 
  and 
  the 
  cleavage 
  

   planes 
  intersect 
  it 
  nearly 
  at 
  right 
  angles. 
  A 
  N.W. 
  and 
  S.E. 
  

   force 
  acting 
  parallel 
  to 
  the 
  present 
  strike 
  in 
  the 
  plane 
  of 
  the 
  

   dip, 
  could 
  not 
  have 
  tilted 
  these 
  portions 
  of 
  the 
  Steep 
  Rock 
  

   Series 
  into 
  their 
  present 
  nearly 
  vertical 
  position. 
  It 
  seems 
  

   necessary' 
  to 
  suppose, 
  therefore, 
  that 
  before 
  the 
  cleavage-pro- 
  

   ducing 
  force 
  acted, 
  that 
  part 
  of 
  the 
  Steep 
  Rock 
  Series 
  that 
  we 
  

   know, 
  existed 
  as 
  a 
  N.W. 
  and 
  S.E. 
  striking 
  monocline, 
  having 
  

   a 
  high 
  dip 
  to 
  the 
  S.W. 
  as 
  the 
  result 
  of 
  previous 
  folding 
  by 
  a 
  

   N.E. 
  and 
  S.W. 
  force. 
  

  

  Fig. 
  2. 
  — 
  Diagram 
  showing 
  the 
  attitude 
  

   of 
  the 
  Steep 
  Rock 
  Series 
  just 
  previous 
  to 
  

   the 
  second 
  folding. 
  

  

  Fig. 
  3. 
  — 
  Diagram 
  showing 
  atti- 
  

   tude 
  of 
  Steep 
  Rock 
  Series 
  after 
  

   second 
  folding. 
  

  

  The 
  folding 
  of 
  the 
  Steep 
  Rock 
  Series 
  indicates 
  therefore 
  

   two 
  periods 
  of 
  orotechnic 
  action. 
  In 
  the 
  first 
  period, 
  the 
  force 
  

   acted 
  in 
  a 
  N.E.-S.W. 
  direction, 
  and 
  folded 
  the 
  series 
  about 
  

   horizontal 
  axes, 
  having 
  a 
  N.W. 
  -S.E. 
  direction. 
  That 
  part 
  of 
  

   the 
  series 
  now 
  exposed 
  about 
  the 
  lake 
  was 
  left 
  as 
  a 
  N.W.- 
  

   striking 
  monocline, 
  with 
  a 
  high 
  dip 
  towards 
  the 
  S.W. 
  In 
  the 
  

   second 
  period, 
  the 
  cleavage-producing 
  force 
  acted 
  in 
  a 
  N.W.- 
  

   S.E. 
  direction 
  upon 
  this 
  monocline 
  and 
  produced 
  upon 
  it 
  two 
  

   effects. 
  1st, 
  it 
  caused 
  it 
  to 
  yield 
  as 
  a 
  whole, 
  not 
  by 
  vertical 
  

   arching 
  over 
  horizontal 
  axes, 
  to 
  which 
  the 
  nearly 
  vertically 
  

  

  