﻿11. 
  L. 
  Smyth 
  — 
  Geology 
  of 
  Steep 
  Hock 
  Lake, 
  Out. 
  323 
  

  

  as 
  a 
  rale, 
  of 
  beds 
  of 
  quartz 
  pebbles, 
  none 
  larger 
  than 
  buckshot, 
  

   with 
  little 
  cement, 
  alternating 
  with 
  layers 
  of 
  massive 
  quartzite. 
  

  

  In 
  crossing 
  from 
  the 
  base 
  of 
  the 
  limestone 
  to 
  the 
  granite 
  it 
  

   becomes 
  at 
  first 
  slightly 
  and 
  then 
  more 
  and 
  more 
  feldspathic 
  

   as 
  the 
  latter 
  is 
  approached. 
  Xear 
  the 
  junction 
  both 
  rocks 
  are 
  

   very 
  similar 
  in 
  composition, 
  so 
  that 
  it 
  is 
  quite 
  impossible 
  to 
  

   draw 
  the 
  line 
  between 
  them 
  from 
  considerations 
  of 
  composition. 
  

   There 
  is 
  an 
  apparent 
  transition 
  from 
  one 
  rock 
  into 
  the 
  other. 
  

   This 
  transition 
  zone, 
  which 
  is 
  from 
  20 
  to 
  30 
  feet 
  in 
  width, 
  is 
  

   uniformly 
  highly 
  schistose, 
  in 
  the 
  regional 
  direction 
  N. 
  43° 
  E., 
  

   which, 
  in 
  the 
  eastern 
  arm, 
  where 
  the 
  strikes 
  are 
  from 
  IN". 
  50° 
  to 
  

   60° 
  W., 
  crosses 
  the 
  courses 
  of 
  the 
  contact 
  and 
  the 
  bedding 
  

   nearly 
  at 
  right 
  angles. 
  The 
  schistose 
  structure 
  is 
  traceable 
  

   through 
  the 
  transition 
  zone 
  into 
  the 
  undoubted 
  granite 
  in 
  

   which 
  it 
  dies 
  out 
  gradually, 
  being 
  represented 
  a 
  few 
  feet 
  away 
  

   by 
  little 
  discontinuous 
  wavy 
  cracks, 
  along 
  which 
  chlorite 
  is 
  

   usually 
  developed, 
  and 
  by 
  a 
  faint 
  foliation. 
  

  

  From 
  these 
  facts 
  it 
  appears 
  certain 
  that 
  the 
  granitic 
  com- 
  

   plex 
  supplied 
  by 
  erosion 
  the 
  materials 
  for 
  Formation 
  I, 
  and 
  

   that 
  the 
  contact 
  is 
  therefore 
  one 
  of 
  unconformability. 
  There 
  

   is 
  no 
  unconformability 
  of 
  structure 
  ; 
  for 
  the 
  only 
  normal 
  struc- 
  

   ture 
  possessed 
  by 
  the 
  basement 
  rocks, 
  that 
  of 
  schistosity, 
  was 
  

   demonstrably 
  imposed 
  upon 
  them 
  at 
  a 
  time 
  long 
  subsequent 
  to 
  

   the 
  accumulation 
  of 
  the 
  various 
  materials 
  which 
  now 
  compose 
  

   the 
  Steep 
  Rock 
  series. 
  The 
  absence 
  of 
  a 
  sharp 
  line 
  of 
  de- 
  

   markation 
  between 
  the 
  complex 
  and 
  Formation 
  I, 
  which 
  may 
  

   seem 
  to 
  be 
  a 
  difficulty 
  in 
  the 
  way 
  of 
  accepting 
  the 
  existence 
  of 
  

   an 
  unconformability, 
  is 
  believed 
  to 
  be 
  capable 
  of 
  a 
  satisfactory 
  

   explanation. 
  In 
  considering 
  the 
  orotechnic 
  history 
  of 
  the 
  

   region 
  the 
  transition 
  zone 
  will 
  be 
  shown 
  to 
  represent, 
  not 
  a 
  

   transition 
  in 
  time, 
  but 
  a 
  mechanical 
  transition 
  in 
  composition, 
  

   dating 
  from 
  a 
  time 
  subsequent 
  to 
  the 
  accumulation 
  of 
  the 
  

   rocks 
  of 
  the 
  Steep 
  Rock 
  series. 
  

  

  Formation 
  II, 
  the 
  lower 
  limestone, 
  lies 
  above 
  Formation 
  I, 
  

   with 
  which 
  it 
  is 
  seen 
  in 
  direct 
  contact 
  at 
  a 
  number 
  of 
  localities. 
  

   The 
  rock 
  is 
  very 
  uniform 
  in 
  character 
  wherever 
  exposed. 
  It 
  

   is 
  a 
  dark 
  to 
  light 
  bluish 
  gray 
  limestone, 
  not 
  at 
  all 
  highly 
  crys- 
  

   talline, 
  often 
  banded 
  with 
  layers 
  of 
  lighter 
  color, 
  along 
  planes 
  

   of 
  original 
  bedding. 
  The 
  light 
  bands 
  vary 
  in 
  width 
  from 
  a 
  

   fine 
  line 
  up 
  to 
  6 
  or 
  8 
  inches. 
  Bedding 
  planes 
  are 
  also 
  often 
  

   marked 
  by 
  thin 
  cherty 
  seams. 
  Basal 
  portions 
  are 
  frequently 
  

   massive 
  and 
  siliceous, 
  and 
  in 
  some 
  localities 
  are 
  highly 
  charged 
  

   with 
  pyrites 
  the 
  decomposition 
  of 
  which 
  causes 
  the 
  rock 
  to 
  

   weather 
  brown. 
  The 
  upper 
  part 
  of 
  the 
  formation 
  is 
  a 
  breccia, 
  

   composed 
  of 
  fragments 
  of 
  limestone, 
  showing 
  original 
  struc- 
  

   ture, 
  and 
  of 
  trap, 
  imbedded 
  in 
  a 
  matrix 
  that 
  seems 
  to 
  be 
  

   mostly 
  made 
  up 
  of 
  a 
  consolidated 
  calcareous 
  flour. 
  It 
  is 
  widely 
  

  

  