﻿ADIRONDACK 
  MAGNETIC 
  IRON 
  ORES 
  59 
  

  

  contain 
  between 
  them 
  reentrant 
  bays 
  or 
  valleys 
  of 
  much 
  gentler 
  

   upward 
  gradient. 
  At 
  the 
  mouth 
  of 
  one 
  of 
  these 
  valleys, 
  yet 
  at 
  the 
  

   summit 
  of 
  a 
  somewhat 
  steep 
  terrace, 
  is 
  the 
  village 
  of 
  Port 
  Henry 
  

   on 
  the 
  200 
  foot 
  contour. 
  To 
  the 
  westward 
  beyond 
  the 
  terrace 
  

   the 
  surface 
  rises 
  again 
  quite 
  steeply 
  to 
  the 
  500 
  foot 
  contour 
  and 
  

   higher. 
  The 
  gentlest 
  gradient 
  is 
  south 
  of 
  the 
  village 
  along 
  the 
  

   valley 
  of 
  McKenzie 
  brook, 
  a 
  line 
  utilized 
  by 
  the 
  Lake 
  Champlain 
  

   & 
  Moriah 
  Railroad, 
  which 
  brings 
  the 
  ore 
  to 
  the 
  docks. 
  The 
  general 
  

   valley 
  is 
  abruptly 
  closed 
  on 
  the 
  south 
  by 
  Bulwagga 
  mountain, 
  a 
  

   steep 
  fault 
  block 
  which 
  fronts 
  Lake 
  Champlain 
  at 
  an 
  altitude 
  of 
  

   1 
  100 
  feet; 
  while 
  on 
  the 
  north, 
  Bald 
  Peak 
  at 
  2055 
  an( 
  ^ 
  ^ 
  s 
  southern 
  

   spurs 
  with 
  declining 
  hights 
  for 
  3 
  miles, 
  stand 
  between 
  the 
  hinter- 
  

   land 
  and 
  the 
  lake. 
  In 
  a 
  general 
  way 
  behind 
  this 
  ridge 
  and 
  forming 
  

   a 
  broad 
  and 
  upward 
  sloping 
  valley 
  lies 
  the 
  heavily 
  drift-covered 
  

   district 
  containing 
  Mineville, 
  which 
  with 
  its 
  mines 
  is 
  situated 
  at 
  

   the 
  foot 
  of 
  the 
  inclosing 
  hills 
  at 
  the 
  north. 
  While 
  a 
  few 
  ledges 
  

   project 
  above 
  the 
  general 
  mantle 
  of 
  sand 
  and 
  boulders 
  within 
  

   the 
  broad 
  valley, 
  yet 
  there 
  are 
  2 
  or 
  3 
  square 
  miles 
  without 
  exposures 
  

   of 
  any 
  kind, 
  and 
  the 
  largest 
  ore 
  bodies 
  themselves 
  must 
  have 
  been 
  

   at 
  the 
  outset 
  covered 
  by 
  at 
  least 
  15 
  or 
  20 
  feet 
  of 
  drift. 
  

  

  If 
  from 
  the 
  summit 
  of 
  some 
  neighboring 
  mountain 
  the 
  observer 
  

   endeavors 
  to 
  eliminate 
  in 
  his 
  imagination 
  the 
  cover 
  of 
  drift 
  and 
  

   restore 
  the 
  old 
  bed-rock 
  topography, 
  the 
  valley 
  becomes 
  one 
  of 
  

   presumably 
  gentle 
  outlines, 
  broken 
  at 
  the 
  foot 
  of 
  many 
  of 
  the 
  

   elevations 
  by 
  steep 
  and 
  somewhat 
  precipitous 
  ledges. 
  The 
  latter 
  

   have 
  been 
  in 
  part, 
  no 
  doubt, 
  freshened 
  up 
  by 
  the 
  erosion 
  of 
  the 
  

   great 
  ice 
  sheet, 
  but 
  they 
  are 
  believed 
  to 
  have 
  been 
  primarily 
  

   caused 
  by 
  faulting. 
  The 
  broad 
  and 
  open 
  character 
  of 
  the 
  valley 
  

   is 
  due 
  to 
  the 
  relatively 
  easy 
  erosion 
  of 
  the 
  rock 
  formations 
  lying 
  

   beneath, 
  since 
  enough 
  exposures 
  can 
  be 
  identified 
  to 
  lead 
  to 
  the 
  

   conclusion 
  that 
  they 
  were 
  once 
  and 
  probably 
  still 
  are 
  in 
  large 
  part 
  

   Precambric 
  or 
  Grenville 
  limestones 
  and 
  their 
  associated 
  sedi- 
  

   ments, 
  whereas 
  the 
  hills 
  are 
  in 
  most 
  though 
  not 
  all 
  cases 
  the 
  harder 
  

   gneisses 
  which 
  are 
  believed 
  to 
  belong 
  to 
  intrusive 
  masses 
  of 
  rock. 
  

  

  These 
  general 
  topographic 
  relations 
  are 
  brought 
  out 
  upon 
  the 
  

   accompanying 
  map 
  [pi. 
  2]. 
  From 
  it 
  we 
  see 
  that 
  Mineville 
  is 
  on 
  the 
  

   1200— 
  1360 
  contours, 
  while 
  the 
  largest 
  mines 
  open 
  on 
  the 
  1300. 
  

   This 
  makes 
  it 
  necessary 
  for 
  the 
  railway 
  to 
  climb 
  1200 
  feet 
  in 
  its 
  

   6 
  miles 
  of 
  track, 
  and 
  since, 
  in 
  the 
  nature 
  of 
  the 
  case, 
  this 
  rise 
  is 
  not 
  

   evenly 
  distributed, 
  the 
  engineering 
  problem 
  presented 
  is 
  one 
  of 
  

   some 
  difficulty. 
  Heavy 
  engines 
  adapted 
  to 
  mountain 
  railways 
  

   are 
  necessary, 
  but 
  as 
  the 
  heaviest 
  traffic 
  is 
  downward, 
  the 
  grades 
  

  

  