﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  IO9 
  

  

  amber 
  crystals 
  of 
  calcite, 
  were 
  also 
  found 
  in 
  these 
  cavities, 
  the 
  com- 
  

   bination 
  being 
  such 
  as 
  to 
  produce 
  specimens 
  of 
  great 
  beauty. 
  

   Among 
  the 
  rarer 
  minerals 
  found 
  in 
  this 
  rock 
  is 
  the 
  crystallized 
  and 
  

   cleavable 
  anhydrite, 
  which 
  like 
  gypsum 
  is 
  a 
  sulfate 
  of 
  calcium, 
  but 
  

   without 
  the 
  water 
  which 
  is 
  characteristic 
  of 
  that 
  mineral. 
  Anhydrite 
  

   crystallizes 
  in 
  the 
  orthorhombic 
  system, 
  and 
  its 
  cleavage 
  is 
  in 
  three 
  

   directions, 
  at 
  right 
  angles 
  to 
  each 
  other 
  (pinacoidal), 
  thus 
  yielding 
  

   rectangular 
  fragments 
  and 
  enabling 
  one 
  to 
  distinguish 
  it 
  from 
  

   selenite 
  with 
  little 
  difficulty. 
  It 
  is 
  also 
  a 
  trifle 
  harder 
  than 
  selenite 
  

   which 
  is 
  easily 
  scratched 
  with 
  the 
  finger 
  nail. 
  This 
  form 
  of 
  anhy- 
  

   drite 
  is 
  rather 
  rare, 
  the 
  principal 
  localities 
  for 
  it 
  being 
  foreign. 
  

   Masses 
  of 
  considerable 
  size 
  have 
  been 
  found 
  in 
  the 
  limestone 
  of 
  this 
  

   quarry, 
  and 
  small 
  pieces 
  are 
  not 
  uncommon 
  in 
  the 
  geodes 
  of 
  these 
  

   strata. 
  Both 
  selenite 
  and 
  the 
  cleavable 
  anhydrite 
  are 
  commonly 
  

   called 
  '' 
  mica 
  " 
  by 
  the 
  uninitiated 
  ; 
  that 
  mineral 
  however 
  does 
  not 
  

   occur 
  at 
  Niagara. 
  Small 
  masses 
  of 
  fibrous 
  gypsum 
  or 
  satin 
  spar 
  

   have 
  been 
  found, 
  but 
  these 
  are 
  very 
  rare. 
  The 
  satin 
  spar 
  of 
  which 
  

   the 
  cheap 
  jewelry 
  sold 
  in 
  the 
  curiosity 
  shops 
  is 
  made 
  is 
  not 
  from 
  

   Niagara. 
  

  

  Among 
  the 
  metallic 
  minerals 
  found 
  in 
  this 
  rock, 
  zinc 
  blende 
  or 
  

   sphalerite 
  is 
  most 
  common. 
  It 
  is 
  generally 
  of 
  a 
  yellowish 
  or 
  light 
  

   brownish 
  color 
  and 
  brilliant 
  resinous 
  luster. 
  Large 
  masses 
  how- 
  

   ever 
  are 
  rare. 
  Galenite 
  or 
  lead 
  sulfid 
  crystals 
  are 
  also 
  occasionally 
  

   found, 
  but 
  this 
  mineral 
  is 
  comparatively 
  rare. 
  In 
  addition 
  to 
  these, 
  

   iron 
  pyrite, 
  iron-copper 
  pyrite 
  (chalcopyrite), 
  green 
  copper 
  carbonate 
  

   (malachite), 
  fluor 
  spar 
  (fluorite), 
  iron 
  carbonate 
  or 
  brown 
  spar 
  

   (siderite, 
  generally 
  ferruginous 
  dolomite), 
  strontium 
  sulfate 
  (celes- 
  

   tite) 
  and 
  native 
  sulfur 
  as 
  well 
  as 
  other 
  minerals 
  are 
  met 
  with. 
  

  

  The 
  total 
  thickness 
  of 
  the 
  limestone 
  exposed 
  in 
  this 
  section 
  is 
  

   thus 
  somewhat 
  more 
  than 
  55 
  feet. 
  At 
  Lewiston 
  hights, 
  on 
  the 
  edge 
  

   of 
  the 
  escarpment, 
  only 
  about 
  20 
  feet 
  are 
  exposed. 
  This 
  includes 
  

   the 
  two 
  lower 
  strata 
  of 
  hydraulic 
  limestone, 
  the 
  crinoidal 
  limestone 
  

   and 
  a 
  few 
  feet 
  of 
  the 
  lowest 
  geodiferous 
  beds 
  (stratum 
  4). 
  Over 
  

   this 
  lie 
  some 
  two 
  or 
  three 
  feet 
  of 
  glacial 
  till. 
  The 
  distance 
  between 
  

   the 
  edge 
  of 
  the 
  escarpment 
  and 
  the 
  quarry 
  at 
  the 
  end 
  of 
  the 
  section, 
  

   is 
  a 
  Httle 
  over 
  a 
  mile 
  and 
  a 
  half, 
  the 
  increase 
  in 
  thickness 
  of 
  the 
  

  

  