﻿50 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  who 
  have 
  worked 
  in 
  the 
  southern 
  fields 
  where 
  the 
  occurrence 
  of 
  rich 
  

   ores 
  at 
  the 
  surface 
  is 
  at 
  times 
  succeeded 
  by 
  lean, 
  limey 
  ores 
  in 
  depth. 
  

  

  The 
  evidence 
  in 
  support 
  of 
  both 
  views 
  has 
  been 
  traversed 
  very 
  

   thoroughly 
  by 
  C. 
  H. 
  Smyth 
  jr, 
  in 
  a 
  paper 
  1 
  which 
  represents 
  as 
  well 
  

   the 
  results 
  of 
  long 
  experience 
  and 
  close 
  study 
  of 
  the 
  Clinton 
  ores 
  

   both 
  in 
  the 
  northern 
  and 
  southern 
  districts. 
  There 
  can 
  be 
  no 
  doubt 
  

   after 
  an 
  impartial 
  perusal 
  of 
  Professor 
  Smyth's 
  paper 
  that 
  the 
  

   theory 
  of 
  sedimentary 
  origin 
  is 
  fully 
  substantiated 
  for 
  most 
  of 
  the 
  

   occurrences. 
  For 
  the 
  ores 
  under 
  present 
  consideration 
  this 
  is 
  the 
  

   only 
  explanation 
  at 
  all 
  compatible 
  with 
  the 
  conditions. 
  

  

  The 
  stratigraphic 
  features 
  presented 
  by 
  the 
  New 
  York 
  section 
  

   of 
  the 
  Clinton 
  do 
  not 
  lend 
  themselves 
  to 
  the 
  conception 
  of 
  vertical 
  

   circulations 
  of 
  ground 
  water 
  such 
  as 
  would 
  be 
  required 
  to 
  dissolve 
  

   and 
  carry 
  iron 
  from 
  .the 
  overlying 
  strata. 
  The 
  ore 
  beds 
  everywhere 
  

   lie 
  nearly 
  horizontal; 
  their 
  dip 
  is 
  universally 
  toward 
  the 
  south 
  at 
  

   an 
  angle 
  no 
  greater 
  probably 
  in 
  many 
  places 
  than 
  that 
  given 
  by 
  

   the 
  contour 
  of 
  the 
  original 
  sea 
  bottom 
  on 
  which 
  they 
  were 
  deposited. 
  

   At 
  no 
  time 
  in 
  their 
  subsequent 
  history 
  have 
  they 
  been 
  steeply 
  in- 
  

   clined. 
  Moreover, 
  they 
  are 
  overlain 
  by 
  thick 
  shales 
  not 
  readily 
  

   permeable 
  to 
  water. 
  Underground 
  flowage 
  must 
  necessarily 
  be 
  

   limited 
  and 
  be 
  dependent 
  for 
  the 
  most 
  part 
  on 
  the 
  cropping 
  out 
  of 
  

   the 
  more 
  porous 
  strata 
  like 
  the 
  limestone 
  and 
  sandstone 
  layers. 
  

   Thus, 
  it 
  is 
  directed 
  rather 
  along 
  the 
  bedding 
  planes 
  than 
  across 
  them. 
  

   Below 
  the 
  ore 
  there 
  is 
  also 
  more 
  or 
  less 
  shale 
  intervening 
  before 
  the 
  

   top 
  of 
  the 
  sandstone 
  and 
  conglomerate 
  basement 
  is 
  reached. 
  

  

  The 
  existence 
  of 
  limestone 
  above 
  the 
  ore 
  beds 
  has 
  been 
  remarked 
  

   by 
  Professor 
  Smyth 
  in 
  the 
  paper 
  already 
  quoted. 
  In 
  Cayuga 
  and 
  

   Wayne 
  counties 
  the 
  fossil 
  hematite 
  is 
  covered 
  directly 
  by 
  limestone 
  

   and 
  there 
  are 
  one 
  or 
  more 
  layers 
  at 
  varying 
  horizons 
  in 
  the 
  shale. 
  

   The 
  main 
  ore 
  bed 
  in 
  this 
  part 
  is 
  generally 
  split 
  into 
  two 
  portions 
  by 
  a 
  

   thin 
  seam 
  of 
  limestone. 
  No 
  noticeable 
  replacement 
  has 
  taken 
  place 
  

   in 
  the 
  overlying 
  limestones, 
  though 
  this 
  would 
  be 
  the 
  first 
  to 
  be 
  

   affected 
  by 
  descending 
  iron-bearing 
  solutions. 
  The 
  limestones 
  are 
  

   fine 
  grained 
  and 
  compact 
  and, 
  where 
  protected 
  by 
  shale, 
  they 
  show 
  

   little 
  effect 
  of 
  leaching 
  in 
  the 
  mass 
  or 
  of 
  solution 
  along 
  the 
  joint 
  

   planes. 
  

  

  The 
  ore 
  beds 
  are 
  separated 
  by 
  sharp 
  division 
  planes 
  above 
  

   and 
  below, 
  with 
  no 
  intervening 
  zone 
  of 
  gradation 
  from 
  ore 
  to 
  

   rock. 
  This 
  feature 
  is 
  well 
  illustrated 
  in 
  the 
  process 
  of 
  open-cut 
  

  

  x 
  Zeits, 
  fiir 
  prak. 
  Geol. 
  Aug. 
  I894. 
  See 
  also 
  paper 
  in 
  Am. 
  Jour. 
  Sci. 
  1892. 
  143:487. 
  

  

  