﻿H. 
  L. 
  Smyth 
  — 
  Geology 
  of 
  Steep 
  Rock 
  Lake, 
  Ont. 
  329 
  

  

  standing 
  leaves 
  of 
  the 
  series 
  would 
  oppose 
  their 
  maximum 
  

   rigidity, 
  but 
  by 
  horizontal 
  buckling 
  about 
  nearly 
  vertical 
  axes, 
  

   to 
  which 
  the 
  opposed 
  rigidity 
  would 
  be 
  a 
  minimum. 
  Figures 
  

   2 
  and 
  3 
  illustrate 
  this 
  point. 
  2nd, 
  consequent 
  upon 
  the 
  

   regional 
  movements 
  attending 
  the 
  folding 
  were 
  produced 
  mi- 
  

   nute 
  fissures, 
  and 
  a 
  rearrangement 
  of 
  particles 
  along 
  planes 
  

   perpendicular 
  to 
  its 
  direction 
  ; 
  or, 
  in 
  other 
  words, 
  the 
  regional 
  

   cleavage. 
  

  

  These 
  two 
  periods 
  of 
  orotechnic 
  action 
  explain 
  also 
  the 
  

   schistose 
  dikes 
  and 
  the 
  transition 
  zones 
  between 
  Formation 
  I, 
  

   and 
  the 
  granitic 
  complex. 
  The 
  dike 
  at 
  locality 
  41 
  will 
  serve 
  

   as 
  an 
  example 
  of 
  the 
  class. 
  It 
  is 
  from 
  60 
  to 
  70 
  feet 
  in 
  width 
  

   and 
  cuts 
  the 
  granitic 
  complex, 
  the 
  southeast 
  wall 
  running 
  "N. 
  

   48° 
  E. 
  For 
  a 
  distance 
  of 
  three 
  feet 
  from 
  the 
  wall 
  the 
  dike 
  is 
  

   very 
  schistose 
  and 
  fine 
  grained. 
  The 
  interior 
  is 
  massive 
  and 
  

   crystalline. 
  Under 
  the 
  microscope 
  the 
  interior 
  is 
  seen 
  to 
  be 
  a 
  

   quartz 
  diorite, 
  consisting 
  of 
  quartz, 
  plagioclose, 
  hornblende, 
  — 
  

   in 
  places 
  altered 
  to 
  chlorite 
  and 
  epidote, 
  magnetite 
  and 
  apatite. 
  

   The 
  feldspars 
  are 
  nearly 
  all 
  saussurized. 
  A 
  slide 
  from 
  the 
  

   schistose 
  portion 
  shows 
  it 
  to 
  be 
  a 
  hydromica 
  schist, 
  with 
  a 
  

   great 
  deal 
  of 
  normal 
  chlorite. 
  The 
  quartzes 
  are 
  strained 
  and 
  

   broken, 
  and 
  the 
  magnetite 
  is 
  granulated 
  and 
  drawn 
  out 
  into 
  

   fissured 
  " 
  augen." 
  Some 
  epidote 
  is 
  arranged 
  along 
  planes 
  of 
  

   foliation. 
  The 
  rock 
  shows 
  shearing 
  and 
  crushing 
  in 
  an 
  eminent 
  

   degree. 
  

  

  Previous 
  to 
  the 
  first 
  orotechnic 
  period 
  we 
  may 
  suppose 
  that 
  

   the 
  Steep 
  Rock 
  series 
  lay 
  in 
  a 
  horizontal 
  position 
  upon 
  the 
  

   basement 
  complex. 
  The 
  parallel 
  dikes, 
  of 
  which 
  41 
  is 
  an 
  

   example, 
  which 
  supplied 
  the 
  materials 
  for 
  the 
  interbedded 
  

   eruptives 
  of 
  the 
  series, 
  constituted 
  a 
  system 
  of 
  thin 
  vertical 
  

   beds 
  running 
  through 
  and 
  binding 
  together 
  the 
  grantitic 
  com- 
  

   plex, 
  and 
  the 
  sediments 
  and 
  interbedded 
  eruptives 
  of 
  the 
  

   upper 
  series. 
  The 
  effect 
  of 
  the 
  first 
  force 
  was 
  to 
  arch 
  the 
  

   series 
  about 
  horizontal 
  axes 
  parallel 
  to 
  the 
  present 
  strikes 
  in 
  

   East 
  Bay, 
  and 
  perpendicular 
  to 
  the 
  course 
  of 
  the 
  chimney 
  

   series 
  of 
  dikes. 
  It 
  acted 
  parallel 
  to 
  the 
  direction 
  of 
  these 
  dikes 
  

   and 
  therefore 
  opposed 
  to 
  their 
  greatest 
  rigidity. 
  As 
  the 
  upper 
  

   series 
  bent 
  under 
  the 
  action 
  of 
  the 
  force, 
  there 
  must 
  have 
  been 
  

   a 
  difference 
  in 
  the 
  rate 
  of 
  yielding 
  of 
  the 
  bedded 
  sediments 
  

   and 
  thin 
  horizontal 
  eruptives, 
  on 
  the 
  one 
  hand, 
  and 
  the 
  verti- 
  

   cal 
  dikes 
  and 
  massive 
  granitic 
  complex 
  on 
  the 
  other. 
  This 
  

   difference 
  in 
  rate 
  of 
  yielding 
  must 
  have 
  produced 
  grinding 
  : 
  

   1st, 
  of 
  the 
  basal 
  sediments 
  on 
  the 
  granitic 
  complex 
  ; 
  2nd, 
  

   between 
  the 
  vertical 
  dikes 
  and 
  the 
  rocks 
  through 
  which 
  they 
  

   passed, 
  whether 
  sediments, 
  interleaved 
  eruptives, 
  or 
  of 
  the 
  

   complex. 
  

  

  The 
  grinding 
  would 
  result 
  in 
  shearing 
  and 
  comminution 
  of 
  

   both 
  rocks 
  in 
  zones 
  adjacent 
  and 
  parallel 
  to 
  the 
  contacts. 
  The 
  

  

  