﻿J2 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  schist, 
  the 
  ore 
  often 
  preserves 
  the 
  appearance 
  of 
  banding 
  and 
  cleav- 
  

   age, 
  and 
  not 
  uncommonly 
  carries 
  a 
  small 
  percentage 
  of 
  graphite, 
  

   the 
  only 
  mineral 
  that 
  seems 
  to 
  have 
  successfully 
  resisted 
  the 
  solvent 
  

   action 
  of 
  the 
  iron-bearing 
  solutions. 
  

  

  As 
  to 
  the 
  source 
  from 
  which 
  the 
  iron 
  has 
  come, 
  the 
  explanation 
  

   advanced 
  by 
  C. 
  H. 
  Smyth 
  jr, 
  merits 
  full 
  acceptance 
  since 
  it 
  meets 
  

   the 
  conditions 
  surrounding 
  the 
  geology 
  of 
  the 
  deposits. 
  His 
  theory 
  

   is- 
  that 
  the 
  iron 
  has 
  been 
  derived 
  from 
  pyrite 
  and 
  magnetite, 
  which 
  

   occur 
  abundantly 
  in 
  the 
  schist 
  in 
  the 
  immediate 
  vicinity 
  of 
  the 
  ore 
  

   bodies. 
  By 
  oxidation 
  the 
  pyrite 
  would 
  yield 
  ferrous 
  and 
  ferric 
  

   sulfates, 
  which 
  would 
  be 
  readily 
  taken 
  up 
  by 
  the 
  underground 
  

   circulations. 
  Free 
  sulfuric 
  acid 
  would 
  also 
  result 
  and 
  react 
  upon 
  

   the 
  veins 
  and 
  disseminations 
  of 
  megnetite. 
  By 
  reaction 
  with 
  the 
  

   limestone 
  and 
  the 
  minerals 
  of 
  the 
  schist, 
  the 
  solutions 
  would 
  de- 
  

   compose 
  and 
  the 
  iron 
  precipitate 
  as 
  carbonate 
  and 
  limonite. 
  By 
  

   subsequent 
  alteration 
  these 
  minerals 
  have 
  been 
  changed 
  to 
  hematite. 
  

   Residual 
  masses 
  of 
  carbonate 
  are 
  occasionally 
  found 
  in 
  the 
  deposits. 
  

   Whenever 
  the 
  Potsdam 
  sandstone 
  is 
  found 
  in 
  contact 
  with 
  the 
  ore, 
  

   the 
  lower 
  layers 
  show 
  a 
  deep 
  iron 
  stain, 
  evidently 
  the 
  effect 
  of 
  

   impregnation 
  by 
  the 
  iron-bearing 
  solutions. 
  

  

  The 
  fourth 
  class 
  of 
  iron 
  ores, 
  the 
  limonites, 
  are 
  not 
  of 
  much 
  im- 
  

   portance 
  in 
  the 
  Adirondack 
  region. 
  The 
  deposits 
  are, 
  as 
  already 
  

   stated, 
  superficial 
  accumulations 
  due 
  to 
  the 
  washing 
  and 
  leaching 
  of 
  

   the 
  neighboring 
  rocks 
  and 
  soils. 
  They 
  seldom, 
  if 
  ever, 
  exist 
  of 
  

   sufficient 
  size 
  and 
  richness 
  to 
  repay 
  working, 
  at 
  least 
  under 
  present 
  

   conditions. 
  

  

  On 
  Tuesday 
  an 
  excursion 
  to 
  Keeseville 
  and 
  the 
  Ausable 
  chasm 
  

   was 
  made 
  by 
  train 
  and 
  tallyho. 
  Professors 
  Wooclworth 
  and 
  Cush- 
  

   ing 
  showed 
  the 
  party 
  the 
  marine 
  delta 
  of 
  the 
  Ausable 
  river, 
  the 
  

   former 
  lake 
  shore 
  lines, 
  the 
  post-Hochelagan 
  gorge 
  of 
  the 
  Ausable 
  

   river 
  cut 
  in 
  Potsdam 
  sandstone, 
  the 
  Potsdam 
  conglomerate, 
  the 
  

   northern 
  slope 
  of 
  Trembleau 
  mountain, 
  and 
  the 
  anorthosite. 
  

  

  In 
  the 
  evening 
  at 
  the 
  Champlain 
  Club 
  Prof. 
  H. 
  P. 
  Cushing 
  dis- 
  

   cussed 
  the 
  

  

  Evidences 
  of 
  physical 
  oscillations 
  during 
  the 
  Cambro-Silurian 
  

   in 
  northeastern 
  New 
  York 
  

  

  as 
  brought 
  out 
  by 
  a 
  general 
  study 
  of 
  the 
  stratigraphy 
  of 
  the 
  region. 
  

   There 
  was 
  a 
  great 
  Potsdam 
  subsidence 
  on 
  the 
  northeast, 
  diminishing 
  

   to 
  zero 
  westward. 
  The 
  succeeding 
  Beekmantown 
  depression 
  en- 
  

   croached 
  further 
  on 
  the 
  land 
  than 
  did 
  the 
  Potsdam 
  on 
  the 
  southern 
  

  

  