﻿66 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  does 
  not 
  wish 
  to 
  discuss 
  at 
  length 
  the 
  points 
  for 
  and 
  against 
  each 
  

   of 
  these 
  views 
  in 
  this 
  place, 
  reserving 
  it 
  for 
  the 
  fuller 
  space 
  which 
  

   will 
  be 
  afforded 
  by 
  a 
  separate 
  bulletin 
  on 
  the 
  Port 
  Henry 
  and 
  

   Elizabethtown 
  quadrangles, 
  now 
  in 
  preparation. 
  If 
  supporters 
  

   of 
  the 
  sedimentary 
  view 
  will 
  add 
  to 
  the 
  rock 
  names 
  used 
  above 
  the 
  

   word 
  gneiss, 
  or 
  change 
  the 
  rock 
  names 
  into 
  the 
  form 
  of 
  adjectives, 
  

   so 
  as 
  to 
  have 
  syenitic 
  gneiss, 
  gabbroic 
  gneiss, 
  dioritic 
  gneiss, 
  etc., 
  

   thus 
  using 
  them 
  as 
  short 
  cuts 
  of 
  expression 
  for 
  the 
  mineralogy 
  of 
  

   the 
  gneisses, 
  they 
  may 
  still 
  be 
  regarded 
  from 
  the 
  point 
  of 
  view 
  of 
  

   sediments. 
  The 
  full 
  discussion 
  requires 
  chemical 
  analyses, 
  and 
  

   more 
  ample 
  illustration. 
  Whether 
  we 
  have, 
  however, 
  parallel 
  

   metamorphosed 
  sediments, 
  or 
  differentiated 
  layers 
  of 
  eruptive 
  

   rock, 
  the 
  structural 
  features 
  of 
  folds 
  and 
  horizons 
  are 
  not 
  changed 
  

   and 
  for 
  practical 
  purposes 
  these 
  are 
  the 
  really 
  important 
  considera- 
  

   tions. 
  The 
  ores, 
  which 
  occur 
  at 
  Mineville 
  as 
  integral 
  members 
  of 
  

   the 
  syenitic 
  series, 
  are 
  in 
  the 
  form 
  of 
  layers 
  conformable 
  to 
  such 
  

   banding 
  or 
  foliation 
  as 
  appears 
  in 
  the 
  rocks. 
  These 
  layers 
  bulge 
  

   and 
  pinch 
  to 
  a 
  remarkable 
  degree, 
  and 
  in 
  the 
  case 
  of 
  the 
  Old 
  Bed 
  

   group 
  (or 
  Mineville 
  group 
  of 
  the 
  writer's 
  earlier 
  paper) 
  extend 
  in 
  a 
  

   practically 
  unbroken 
  stretch 
  for 
  half 
  a 
  mile 
  exhibiting 
  at 
  the 
  same 
  

   time 
  a 
  very 
  complex 
  and 
  puzzling 
  fold 
  ; 
  while 
  in 
  the 
  Barton 
  Hill 
  

   group 
  the 
  extent 
  is 
  still 
  longer 
  but 
  the 
  structure 
  is 
  simpler. 
  The 
  so 
  

   called 
  Cheever 
  bed 
  with 
  its 
  extensions 
  must 
  be 
  fully 
  half 
  a 
  mile 
  in 
  

   length, 
  but 
  all 
  the 
  others 
  are 
  smaller. 
  The 
  bulges 
  and 
  pinches 
  give 
  

   a 
  marked 
  podlike 
  or 
  lenticular 
  form 
  so 
  that 
  at 
  Mineville 
  the 
  ore 
  

   bodies 
  are 
  a 
  series 
  of 
  richer 
  and 
  thicker 
  shoots 
  whose 
  long 
  axes 
  

   run 
  in 
  a 
  parallel 
  northeast 
  and 
  southwest 
  direction. 
  

  

  The 
  ores 
  are 
  granular 
  masses 
  of 
  magnetite 
  which 
  in 
  the 
  Barton 
  

   Hill 
  group 
  were 
  prevailingly 
  of 
  Bessemer 
  grade, 
  but 
  which 
  in 
  the 
  

   Old 
  Bed 
  series 
  are 
  high 
  in 
  phosphorus 
  from 
  disseminated 
  apatite. 
  

   These 
  are 
  now 
  run 
  through 
  a 
  magnetic 
  mill 
  and 
  freed 
  of 
  the 
  apatite 
  

   to 
  such" 
  a 
  degree 
  that 
  they 
  are 
  a 
  better 
  grade 
  for 
  the 
  furnace 
  and 
  the 
  

   apatite 
  is 
  salable 
  for 
  fertilizers. 
  Occasionally 
  where 
  the 
  apatite 
  

   is 
  relatively 
  abundant 
  and 
  the 
  ore 
  occurs 
  near 
  a 
  fault 
  or 
  line 
  of 
  

   crushing 
  which 
  has 
  caused 
  decomposition 
  of 
  the 
  augite 
  both 
  in 
  the 
  

   ore 
  and 
  in 
  the 
  country 
  rock, 
  red 
  hematite 
  has 
  been 
  yielded 
  and 
  has 
  

   filtered 
  into 
  all 
  the 
  little 
  crevices 
  and 
  has 
  given 
  the 
  ore 
  a 
  red 
  color. 
  

   This 
  variety 
  is 
  the 
  so 
  called 
  "red 
  ore" 
  of 
  the 
  cross-section. 
  In 
  

   the 
  same 
  way 
  the 
  country 
  rock 
  is 
  also 
  colored 
  red. 
  

  

  In 
  thin 
  section 
  the 
  rich 
  Old 
  Bed 
  ore 
  reveals 
  a 
  noticeable 
  amount 
  

   of 
  the 
  green 
  augite, 
  characteristic 
  of 
  the 
  syenitic 
  wall 
  rock. 
  This 
  

   mineral 
  has 
  certain 
  optical 
  properties 
  that 
  suggest 
  a 
  variety 
  rich 
  in 
  

  

  