﻿H. 
  L. 
  Smyth 
  — 
  Geology 
  of 
  Steep 
  Booh 
  Lake, 
  Out. 
  317 
  

  

  facts 
  that 
  would 
  support 
  this 
  view, 
  especially 
  the 
  very 
  rich 
  and 
  

   varied 
  coloration 
  of 
  the 
  subsalts 
  corresponding 
  to 
  the 
  almost 
  

   infinite 
  variety 
  of 
  color 
  of 
  allotropic 
  silver, 
  while 
  normal 
  salts 
  

   of 
  silver 
  when 
  formed 
  with 
  colorless 
  acids 
  are 
  mostly 
  colorless. 
  

   On 
  the 
  other 
  hand, 
  the 
  greater 
  activity 
  of 
  allotropic 
  silver 
  and 
  

   its 
  less 
  specific 
  gravity 
  would 
  seem 
  to 
  indicate 
  a 
  simpler 
  

   molecular 
  constitution 
  than 
  that 
  of 
  normal 
  silver. 
  

  

  Aet. 
  XXXI. 
  — 
  Structural 
  Geology 
  of 
  Steep 
  Rock 
  Lake, 
  On- 
  

   tario 
  ; 
  by 
  Heney 
  Lloyd 
  Smyth. 
  With 
  Plate 
  XL 
  

  

  Geogeaphy. 
  

  

  Steep 
  Rock 
  Lake 
  is 
  situated 
  in 
  the 
  Province 
  of 
  Ontario, 
  

   Canada, 
  northwest 
  of 
  Lake 
  Superior 
  and 
  south 
  of 
  the 
  Can- 
  

   adian 
  Pacific 
  Railway. 
  It 
  lies 
  about 
  twenty-five 
  miles 
  east 
  of 
  

   the 
  center 
  of 
  the 
  rough 
  quadrilateral 
  formed 
  by 
  the 
  Canadian 
  

   Pacific 
  Railway 
  on 
  the 
  northeast, 
  the 
  Lake 
  of 
  the 
  Woods 
  on 
  

   the 
  northwest, 
  the 
  United 
  States 
  boundary 
  on 
  the 
  southwest, 
  

   and 
  the 
  shore 
  of 
  Lake 
  Superior 
  from 
  Pigeon 
  River 
  to 
  Port 
  

   Arthur, 
  on 
  the 
  southeast'. 
  As 
  given 
  on 
  the 
  map 
  of 
  the 
  Prov- 
  

   ince, 
  scale 
  1 
  inch 
  = 
  30 
  miles, 
  published 
  by 
  the 
  Crown 
  Lands 
  

   Department, 
  Toronto, 
  L884, 
  the 
  geographical 
  position 
  of 
  the 
  

   extreme 
  southern 
  point 
  of 
  the 
  lake, 
  where 
  it 
  receives 
  the 
  

   waters 
  of 
  the 
  Aticokan 
  River 
  from 
  the 
  east, 
  is 
  about 
  lat. 
  48° 
  

   52' 
  X. 
  and 
  long. 
  91° 
  30' 
  W. 
  from 
  Greenwich; 
  or, 
  it 
  is 
  about 
  

   halfway 
  upon 
  the 
  map 
  between 
  Lac 
  des 
  Milles 
  Lacs 
  and 
  Rainy 
  

   Lake. 
  

  

  Topogkaphy. 
  

  

  Steep 
  Rock 
  Lake 
  is 
  one 
  of 
  the 
  many 
  that, 
  collectively, 
  con- 
  

   nected 
  by 
  longer 
  or 
  shorter 
  links 
  of 
  river 
  make 
  up 
  the 
  River 
  

   Seine 
  from 
  Island 
  Falls 
  as 
  far 
  as, 
  and 
  doubtless 
  below, 
  the 
  

   Aticokan 
  River. 
  In 
  shape 
  the 
  lake 
  resembles, 
  as 
  shown 
  on 
  

   the 
  map, 
  an 
  irregular 
  and 
  slightly 
  distorted 
  letter 
  M, 
  of 
  which 
  

   the 
  western 
  or 
  left 
  arm, 
  (looking 
  north), 
  runs 
  north 
  and 
  south, 
  

   and 
  the 
  eastern 
  or 
  right 
  arm 
  northwest 
  and 
  southeast. 
  This 
  

   peculiar 
  form 
  is 
  closely 
  related 
  to 
  the 
  character 
  and 
  to 
  the 
  

   structure 
  of 
  the 
  rocks 
  in 
  which 
  the 
  lake 
  lies 
  as 
  will 
  be 
  seen 
  in 
  

   what 
  follows. 
  The 
  Seine 
  River, 
  after 
  a 
  beautiful 
  fall, 
  two 
  

   hundred 
  feet 
  across, 
  and 
  forty 
  to 
  fifty 
  feet 
  high, 
  over 
  granite, 
  

   some 
  three 
  hundred 
  yards 
  northeast 
  of 
  the 
  lake, 
  flows 
  into 
  it 
  

   at 
  a 
  point 
  about 
  a 
  mile 
  southeast 
  of 
  the 
  northwest 
  extremity 
  of 
  

   the 
  eastern 
  arm. 
  It 
  leaves 
  the 
  lake 
  at 
  the 
  extreme 
  southern 
  

   end 
  of 
  the 
  western 
  arm. 
  Between 
  the 
  points 
  of 
  entrance 
  and 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Third 
  Series, 
  Vol. 
  XLII, 
  No. 
  250. 
  — 
  October, 
  1891. 
  

   22 
  

  

  