﻿14 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  development 
  of 
  mining 
  and 
  diamond 
  drilling 
  in 
  the 
  great 
  iron 
  ore 
  

   bodies 
  at 
  Mineville 
  and 
  it 
  has 
  been 
  desirable 
  to 
  bring 
  the 
  records 
  

   up 
  to 
  date. 
  There 
  lies 
  between 
  the 
  boundary 
  of 
  the 
  Elizabeth- 
  

   town 
  quadrangle 
  and 
  Lake 
  Champlain 
  a 
  comparatively 
  narrow 
  belt 
  

   of 
  country 
  in 
  the 
  Port 
  Henry 
  quadrangle 
  which 
  it 
  has 
  seemed 
  de- 
  

   sirable 
  to 
  treat 
  together 
  with 
  the 
  former, 
  and 
  as 
  the 
  latter 
  includes 
  

   areas 
  of 
  Paleozoic 
  sedimentaries 
  the 
  assistance 
  of 
  Dr 
  Ruedemann 
  

   was 
  enlisted 
  in 
  the 
  solution 
  of 
  problems 
  involved 
  in 
  the 
  mapping 
  

   of 
  these. 
  The 
  season's 
  work, 
  thus, 
  has 
  been 
  largely 
  devoted 
  to 
  

   (i) 
  reviewing 
  and 
  plotting 
  new 
  data 
  in 
  regard 
  to 
  the 
  Mineville 
  

   ores, 
  (2) 
  verifying 
  and 
  amplifying 
  observations 
  on 
  the 
  Elizabeth- 
  

   town 
  quadrangle, 
  (3) 
  traversing 
  the 
  Precambric 
  formations 
  of 
  the 
  

   Port 
  Henry 
  sheet. 
  In 
  general 
  beneath 
  the 
  undoubted 
  sediments 
  of 
  

   the 
  Grenville 
  and 
  intimately 
  involved 
  with 
  them 
  along 
  the 
  borders 
  

   there 
  is 
  a 
  great 
  series 
  of 
  rocks 
  usually 
  gneissoid 
  but 
  often 
  massive, 
  

   of 
  a 
  mineralogy 
  ranging 
  from 
  the 
  granites 
  through 
  the 
  syenites 
  to 
  

   and 
  into 
  acidic 
  diorites 
  which 
  are 
  probably 
  of 
  intrusive 
  origin 
  and 
  

   which 
  represent- 
  one 
  or 
  more 
  great 
  bathyliths. 
  Though 
  at 
  times 
  

   decidedly 
  variable 
  in 
  composition 
  this 
  may 
  well 
  be 
  due 
  to 
  the 
  fusing 
  

   into 
  their 
  substance 
  of 
  the 
  Grenville 
  sediments, 
  which 
  range 
  from 
  

   quartzites 
  to 
  limestones. 
  The 
  whole 
  aggregate 
  has 
  been 
  extensively 
  

   faulted. 
  Distinct 
  from 
  this 
  complex 
  are 
  the 
  anorthosites 
  and 
  some 
  

   related 
  gabbros, 
  but 
  between 
  the 
  anorthosites 
  and 
  the 
  syenites 
  there 
  

   are 
  intermediate 
  transitions 
  which 
  add 
  to 
  the 
  difficulty 
  of 
  sharply 
  

   defined 
  mapping. 
  

  

  Valcour 
  island, 
  Lake 
  Champlain. 
  Prof. 
  George 
  H. 
  Hudson 
  is 
  

   finishing 
  the 
  survey 
  of 
  the 
  eastern 
  shore 
  of 
  Valcour 
  island 
  on 
  the 
  

   scale 
  of 
  1 
  :iooo 
  and 
  proposes 
  to 
  reduce 
  the 
  remainder 
  of 
  the 
  island 
  

   to 
  one 
  of 
  1 
  -.3000. 
  

  

  The 
  chief 
  reason 
  for 
  continuing 
  the 
  survey 
  on 
  this 
  large 
  scale 
  

   is 
  the 
  fact 
  that 
  the 
  region 
  is 
  one 
  of 
  curiously 
  changing 
  dip 
  and 
  

   strike. 
  It 
  has 
  been 
  influenced 
  not 
  only 
  by 
  east 
  and 
  west 
  faults 
  

   together 
  with 
  some 
  compression, 
  but 
  the 
  influence 
  of 
  a 
  great 
  and 
  

   somewhat 
  distributed 
  north 
  and 
  south 
  fault 
  close 
  to 
  the 
  east 
  edge 
  

   of 
  the 
  island 
  is 
  very 
  apparent. 
  The 
  southwesterly 
  section 
  has 
  been 
  

   remeasured 
  and 
  some 
  important 
  corrections 
  made, 
  and 
  the 
  east 
  

   section 
  of 
  the 
  island 
  worked 
  out 
  with 
  good 
  exactitude. 
  This 
  is 
  the 
  

   most 
  important 
  section 
  of 
  the 
  island, 
  because 
  its 
  beds 
  present 
  a 
  

   hundred 
  times 
  the 
  area 
  of 
  the 
  south 
  section. 
  

  

  An 
  interesting 
  result 
  of 
  this 
  investigation 
  is 
  the 
  recognition 
  of 
  

   the 
  repetition 
  of 
  the 
  coral 
  and 
  stromatoporoid 
  reefs 
  in 
  the 
  Chazy 
  

  

  