﻿GEOLOGY 
  OF 
  WASHINGTON, 
  WARREN 
  COUNTIES, 
  ETC. 
  541 
  

  

  Horicon 
  

  

  Topography. 
  Horicon 
  is 
  a 
  large 
  township, 
  which 
  lies 
  along 
  

   the 
  eastern 
  side 
  of 
  Schroon 
  lake 
  and 
  Schroon 
  river, 
  and 
  extends 
  

   eastward 
  so 
  as 
  to 
  include 
  Brant 
  lake, 
  a 
  large 
  body 
  of 
  water, 
  in 
  

   its 
  southern, 
  central 
  part. 
  It 
  is 
  bounded 
  on 
  the 
  east 
  by 
  Hague, 
  

   no 
  topographic 
  feature 
  marking 
  the 
  border. 
  Horicon 
  is 
  hilly 
  

   and 
  diversified 
  with 
  few 
  elevations 
  of 
  notable 
  hight. 
  It 
  is 
  pro- 
  

   vided 
  with 
  a 
  great 
  number 
  of 
  small 
  ponds. 
  

  

  Series 
  1. 
  The 
  gneisses 
  in 
  Horicon 
  are 
  of 
  a 
  granitic 
  mineralogy 
  

   in 
  most 
  cases. 
  They 
  are 
  strongly 
  laminated 
  and 
  contain 
  much 
  

   biotite. 
  The 
  prevailing 
  feldspar 
  is 
  apparently 
  orthoclase 
  or 
  

   microcline, 
  but 
  they 
  have 
  not 
  been 
  determined 
  by 
  the 
  microscope 
  

   and 
  the 
  statement 
  depends 
  on 
  their 
  similarity 
  to 
  other 
  known 
  

   forms. 
  Just 
  north 
  of 
  the 
  village 
  of 
  Horicon 
  is 
  a 
  hill 
  on 
  which 
  

   is 
  located 
  a 
  quarry 
  that 
  has 
  given 
  excellent 
  exposures 
  of 
  the 
  

   country 
  rock. 
  The 
  latter 
  is 
  now 
  a 
  coarsely 
  prophyritic 
  variety 
  

   whose 
  large 
  pink 
  feldspars 
  1-2 
  in. 
  (or 
  25-50 
  mm 
  across) 
  are 
  pretty 
  

   thoroughly 
  granulated 
  microline. 
  The 
  groundmass 
  is 
  a 
  mix- 
  

   ture 
  of 
  brown 
  and 
  green 
  biotite, 
  quartz, 
  greenish 
  orthoclase 
  and 
  

   plagioclase, 
  thoroughly 
  granulated 
  into 
  particles 
  -| 
  inch 
  (3 
  mm) 
  

   and 
  less 
  in 
  diameter. 
  Zircons, 
  apatite, 
  magnetite 
  and 
  pyrite 
  are 
  

   also 
  present. 
  The 
  rock 
  lacks 
  gneissoid 
  foliation 
  to 
  a 
  great 
  degree 
  

   in 
  the 
  quarry, 
  but 
  it 
  assumes 
  it 
  strongly 
  on 
  the 
  north 
  face 
  of 
  the 
  

   hill. 
  This 
  exposure 
  is 
  of 
  the 
  highest 
  significance, 
  because 
  it 
  

   gives 
  us 
  the 
  clue 
  to 
  the 
  derivation 
  of 
  some 
  thoroughly 
  gneissoid 
  

   and 
  even 
  schistose 
  varieties 
  from 
  a 
  massive 
  granite 
  porphyry. 
  

   Somewhat 
  similar 
  porphyries 
  have 
  been 
  already 
  recognized 
  in 
  

   Ticonderoga, 
  Bolton 
  and 
  Whitehall, 
  in 
  addition 
  to 
  Horicon, 
  and 
  

   their 
  schistose 
  derivations 
  when 
  once 
  the 
  passage 
  is 
  established 
  

   so 
  that 
  the 
  varieties 
  can 
  be 
  recognized, 
  will 
  be 
  found 
  we 
  are 
  con- 
  

   fident 
  in 
  many 
  places. 
  An 
  important 
  step 
  results 
  in 
  solving 
  

   these 
  metamorphic 
  problems. 
  The 
  specimens 
  on 
  which 
  the 
  above 
  

   statements 
  are 
  based 
  are 
  no. 
  128 
  and 
  129. 
  At 
  130 
  near 
  Round 
  

   pond 
  the 
  gneiss 
  is 
  a 
  sheared 
  granite 
  and 
  is 
  finely 
  laminated; 
  138 
  

   is 
  similar 
  from 
  a 
  point 
  a 
  mile 
  east. 
  At 
  140 
  a 
  little 
  further 
  south- 
  

   east 
  a 
  greenish 
  rock 
  like 
  the 
  Whitehall 
  type 
  of 
  syenite-gneiss, 
  

  

  