﻿10 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  GENERAL 
  GEOLOGY 
  

  

  Principal 
  publications. 
  The 
  geology 
  of 
  the 
  Adirondacks 
  was 
  

   investigated 
  in 
  the 
  early 
  part 
  of 
  the 
  last 
  century 
  by 
  Prof. 
  E. 
  

   Emmons 
  under 
  commission 
  of 
  the 
  Natural 
  History 
  Survey 
  of 
  New 
  

   York 
  State. 
  The 
  final 
  report 
  of 
  Emmons, 
  which 
  was 
  published 
  in 
  

   1842, 
  contains 
  a 
  vast 
  collection 
  of 
  observations 
  on 
  the 
  topography, 
  

   rocks, 
  stratigraphy 
  and 
  mineral 
  resources 
  of 
  the 
  region, 
  consti- 
  

   tuting 
  a 
  valuable 
  reference 
  work 
  to 
  this 
  day. 
  The 
  notes 
  on 
  the 
  iron 
  

   ores 
  and 
  the 
  iron 
  mining 
  industry 
  are 
  commendable 
  for 
  their 
  detail 
  

   and 
  accuracy. 
  Professor 
  Emmons 
  considered 
  the 
  rocks 
  to 
  be 
  mainly 
  

   " 
  primary 
  " 
  and 
  divided 
  them 
  into 
  the 
  classes 
  of 
  unstratified, 
  

   stratified 
  and 
  subordinate. 
  Among 
  the 
  unstratified 
  rocks 
  he 
  

   grouped 
  granite, 
  hypersthene 
  rock 
  (anorthosite) 
  , 
  limestone, 
  ser- 
  

   pentine, 
  and 
  rensselaerite. 
  The 
  stratified 
  class 
  included 
  gneiss, 
  

   hornblende 
  (hornblende 
  gneiss 
  and 
  amphibolite) 
  , 
  syenite 
  and 
  talc. 
  

   The 
  subordinate 
  rocks 
  were 
  porphyry, 
  trap, 
  magnetite 
  and 
  specular 
  

   iron 
  ores. 
  The 
  stratigraphic 
  sequence 
  of 
  the 
  formations 
  received 
  

   little 
  attention 
  as, 
  indeed, 
  the 
  question 
  involved 
  problems 
  that 
  

   could 
  scarcely 
  be 
  met 
  by 
  the 
  methods 
  and 
  opportunities 
  which 
  

   were 
  at 
  Professor 
  Emmons's 
  disposal. 
  

  

  A 
  paper 
  by 
  C. 
  E. 
  Hall, 
  published 
  in 
  the 
  report 
  of 
  the 
  New 
  York 
  

   State 
  Museum 
  for 
  1878, 
  contains 
  a 
  description 
  of 
  some 
  of 
  the 
  iron 
  

   ore 
  deposits 
  of 
  the 
  eastern 
  Adirondacks. 
  The 
  ores 
  are 
  stated 
  to 
  be 
  

   associated 
  with 
  the 
  following 
  rock 
  groups: 
  Lower 
  Laurentian 
  

   magnetic 
  iron 
  ore 
  series; 
  Laurentian 
  sulfur 
  ore 
  series; 
  and 
  the 
  

   Upper 
  Laurentian, 
  or 
  limestones 
  and 
  Labrador 
  series, 
  with 
  titanic 
  

   iron 
  ores. 
  In 
  a 
  note 
  to 
  the 
  article 
  the 
  classification 
  is 
  amended 
  by 
  

   placing 
  the 
  limestones 
  in 
  a 
  separate 
  group 
  with 
  an 
  unconformity 
  

   at 
  their 
  base 
  where 
  they 
  rest 
  upon 
  the 
  Upper 
  Laurentian. 
  

  

  In 
  the 
  last 
  15 
  years 
  a 
  geological 
  investigation 
  of 
  the 
  Adirondacks, 
  

   wider 
  in 
  scope 
  than 
  any 
  previously 
  undertaken, 
  has 
  been 
  in 
  progress 
  

   under 
  the 
  direction 
  of 
  the 
  State 
  Geologist. 
  The 
  field 
  work 
  has 
  been 
  

   carried 
  out 
  principally 
  by 
  Prof. 
  J. 
  F. 
  Kemp, 
  C. 
  H. 
  Smyth 
  jr, 
  and 
  

   H. 
  P. 
  Cushing. 
  Their 
  efforts 
  until 
  recently 
  have 
  been 
  directed 
  

   toward 
  a 
  general 
  reconnaissance 
  as 
  a 
  preliminary 
  to 
  a 
  detailed 
  

   survey 
  which 
  was 
  necessarily 
  deferred 
  until 
  accurate 
  base 
  maps 
  

   could 
  be 
  prepared. 
  The 
  results 
  have 
  appeared 
  from 
  time 
  to 
  time 
  

   in 
  the 
  bulletins 
  and 
  reports 
  of 
  the 
  New 
  York 
  State 
  Museum. 
  Much 
  

   has 
  been 
  done 
  to 
  clear 
  up 
  the 
  main 
  problems 
  connected 
  with 
  the 
  

   lithologic 
  and 
  stratigraphic 
  relations 
  of 
  the 
  rocks, 
  and 
  it 
  may 
  be 
  

   said 
  that 
  the 
  principles 
  for 
  the 
  interpretation 
  of 
  the 
  geology 
  of 
  the 
  

  

  