﻿GEOLOGY 
  OF 
  WASHINGTON, 
  WARREN 
  COUNTIES, 
  ETC. 
  507 
  

  

  observed 
  to 
  be 
  so 
  thoroughly 
  gneissoid 
  that 
  the 
  microperthitic 
  

   structure 
  was 
  regarded, 
  in 
  accordance 
  with 
  widely 
  prevalent 
  

   views 
  of 
  it, 
  as 
  a 
  result 
  of 
  metamorphism. 
  Meantime 
  an 
  import- 
  

   ant 
  memoir 
  by 
  F. 
  Kolderup 
  a 
  has 
  appeared 
  upon 
  an 
  area 
  of 
  

   labradorite 
  rocks 
  near 
  Soggendal, 
  Norway, 
  in 
  which 
  true 
  igneous 
  

   types 
  containing 
  microperthite 
  and 
  dark 
  silicates 
  in 
  quantity, 
  

   are 
  described 
  as 
  associated 
  with 
  anorthosites; 
  and 
  Prof. 
  Cush- 
  

   ing 
  has 
  found 
  them 
  near 
  Loonlake 
  station, 
  Franklin 
  co., 
  6 
  in 
  

   perfectly 
  massive 
  form 
  and 
  containing 
  angular 
  inclusions 
  of 
  

   gneisses 
  belonging 
  to 
  the 
  series 
  of 
  the 
  crystalline 
  limestones. 
  

   This 
  latter 
  discovery 
  was 
  a 
  most 
  important 
  addition 
  to 
  our 
  knowl- 
  

   edge 
  of 
  the 
  Adirondacks 
  and 
  has 
  aided 
  to 
  clear 
  up 
  many 
  obscure 
  

   and 
  puzzling 
  facts 
  which 
  have 
  been 
  often 
  observed 
  by 
  one 
  of 
  us 
  

   (J. 
  F. 
  Kemp). 
  The 
  Loonlake, 
  6 
  Franklin 
  co., 
  rocks 
  are 
  regarded 
  

   by 
  Prof. 
  Cushing, 
  doubtless 
  with 
  entire 
  correctness, 
  as 
  belong- 
  

   ing 
  to 
  the 
  eruptive 
  series 
  of 
  which 
  the 
  labradorite 
  rocks 
  are 
  the 
  

   leading 
  members, 
  but 
  as 
  they 
  are 
  in 
  highly 
  gneissoid 
  development 
  

   in 
  the 
  area 
  here 
  described, 
  and 
  as 
  they 
  are 
  far 
  from 
  the 
  labradorite 
  

   rocks, 
  they 
  are 
  mentioned 
  in 
  the 
  general 
  series 
  of 
  gneisses. 
  For 
  

   convenience 
  they 
  will 
  be 
  called 
  the 
  " 
  Whitehall 
  type 
  " 
  of 
  gneiss 
  

   because 
  they 
  are 
  abundant 
  in 
  Whitehall, 
  just 
  in 
  the 
  southwestern 
  

   outskirts 
  of 
  the 
  village, 
  where 
  they 
  are 
  quarried 
  for 
  under- 
  

   pinning. 
  We 
  may 
  therefore 
  safely 
  refer 
  to 
  an 
  original 
  eruptive 
  

   rock, 
  all 
  the 
  dark 
  green 
  gneisses 
  that 
  have 
  this 
  mineralogical 
  

   composition, 
  however 
  strongly 
  foliated 
  they 
  may 
  be 
  now. 
  

  

  3 
  In 
  a 
  former 
  report 
  by 
  one 
  of 
  us, 
  d 
  a 
  coarse 
  porphyritic 
  rock 
  of 
  

   the 
  general 
  mineralogy 
  of 
  a 
  diorite 
  was 
  mentioned. 
  Somewhat 
  

   similar 
  ones 
  were 
  found 
  in 
  several 
  places 
  during 
  the 
  field 
  work 
  of 
  

   1897, 
  but 
  most 
  important 
  of 
  all 
  is 
  a 
  hill 
  north 
  of 
  the 
  village 
  of 
  

   Horicon, 
  that 
  is 
  a 
  coarse 
  granite-porphyry.. 
  It 
  has 
  large 
  pink, 
  but 
  

   thoroughly 
  granulated 
  phenocrysts 
  of 
  microcline 
  in 
  a 
  rather 
  

  

  aF. 
  Kolderup. 
  Die 
  Labradorfelsen 
  des 
  westlichen 
  Norwegens. 
  Bergen's 
  Museum's 
  Aarbog, 
  

   1896, 
  5. 
  

  

  bH. 
  P. 
  Cushing 
  Augite 
  syenite 
  near 
  Loon 
  Lake, 
  N. 
  Y. 
  Read 
  at 
  meeting 
  of 
  Geological 
  society 
  of 
  

   America, 
  Dec 
  . 
  1898 
  . 
  Bulletin 
  of 
  the 
  society, 
  10 
  :1?7 
  . 
  

  

  e 
  Loonlake, 
  Franklin 
  co., 
  on 
  the 
  Chateaugay 
  R. 
  R. 
  and 
  the 
  N. 
  Y. 
  C. 
  R. 
  R., 
  is 
  not 
  to 
  be 
  confused 
  

   with 
  Loonlake, 
  in 
  Chester 
  township, 
  Warren 
  co. 
  

  

  d 
  J. 
  F.Kemp. 
  1893. 
  Remarks 
  on 
  Ticonderoga, 
  p. 
  454. 
  

  

  