﻿510 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  than 
  some 
  that 
  have 
  been 
  noted 
  in 
  Essex 
  co. 
  Terraces 
  dating 
  

   from 
  the 
  time 
  of 
  the 
  retreat 
  of 
  the 
  ice 
  sheet 
  are 
  of 
  marked 
  de- 
  

   velopment 
  in 
  both 
  the 
  Champlain 
  valley 
  and 
  along 
  the 
  Hudson. 
  

   Under 
  the 
  township 
  geology 
  we 
  have 
  remarked 
  their 
  presence 
  

   and 
  have 
  cited 
  the 
  papers 
  that 
  have 
  thus 
  far 
  been 
  written, 
  but 
  

   the 
  field 
  is 
  a 
  practically 
  unexplored 
  one, 
  and 
  except 
  for 
  an 
  occa- 
  

   sional 
  stray 
  note, 
  we 
  have 
  given 
  it 
  slight 
  attention. 
  

  

  In 
  southern 
  Warren 
  co. 
  there 
  is 
  a 
  peculiar 
  tendency 
  of 
  the 
  

   streams 
  to 
  leave 
  the 
  normal 
  southerly 
  courses 
  and 
  double 
  back 
  

   on 
  themselves 
  to 
  the 
  northeast 
  again. 
  This 
  is 
  pronounced 
  in 
  

   the 
  case 
  of 
  the 
  Sacondaga 
  and 
  the 
  Hudson. 
  The 
  Sacondaga 
  

   makes 
  a 
  very 
  acute 
  angle 
  with 
  its 
  old 
  direction, 
  and 
  the 
  Hudson 
  

   behaves 
  in 
  an 
  almost 
  identical 
  way 
  although 
  it 
  later 
  resumes 
  a 
  

   southerly 
  course. 
  Prof. 
  G. 
  F. 
  Wright, 
  as 
  subsequently 
  cited 
  under 
  

   Whitehall, 
  has 
  noted 
  an 
  old 
  channel 
  of 
  the 
  Hudson 
  leading 
  to 
  

   the 
  south 
  near 
  Corinth, 
  but 
  regarding 
  the 
  Sacondaga 
  we 
  have 
  no 
  

   data 
  to 
  determine 
  the 
  diverting 
  course. 
  

  

  In 
  the 
  following 
  descriptions 
  the 
  same 
  provisional 
  names 
  for 
  

   the 
  formations 
  will 
  be 
  employed 
  as 
  in 
  former 
  reports. 
  The 
  

   stratigraphic 
  demarcation 
  between 
  series 
  1 
  and 
  series 
  2 
  is 
  not 
  

   sharp. 
  The 
  limestones 
  may 
  be 
  but 
  minor 
  members, 
  perhaps 
  

   several 
  times 
  repeated 
  in 
  series 
  1, 
  but 
  they 
  are 
  lithologically 
  

   distinct 
  and 
  peculiar. 
  They 
  are 
  quite 
  abundant 
  in 
  Warren 
  co. 
  

  

  Series 
  1. 
  Gneisses 
  usually 
  with 
  both 
  orthoclase 
  or 
  microper- 
  

   thite 
  and 
  quartz. 
  Varieties 
  with 
  hornblende, 
  biotite 
  and 
  

   pyroxene 
  and 
  with 
  almost 
  no 
  dark 
  silicate, 
  are 
  met. 
  Plagioclase 
  

   is 
  usually 
  present 
  and 
  may 
  be 
  the 
  only 
  feldspar. 
  The 
  exposures 
  

   vary 
  in 
  color 
  from 
  very 
  light 
  gray, 
  almost 
  white, 
  to 
  dark 
  gray 
  

   or 
  even 
  to 
  red. 
  The 
  foliation 
  may 
  be 
  conspicuous 
  or 
  may 
  almost 
  

   fail. 
  Two 
  types 
  of 
  gneiss 
  have 
  been 
  specially 
  noted; 
  the 
  

   " 
  Whitehall/' 
  usually 
  dark 
  green 
  in 
  color, 
  and 
  composed 
  of 
  

   microperthite, 
  some 
  plagioclase, 
  varying 
  amounts 
  of 
  quartz, 
  emer- 
  

   ald 
  green 
  augite, 
  dark 
  brown 
  hornblende, 
  often 
  hypersthene, 
  and 
  

   sometimes 
  garnets; 
  the 
  " 
  Horicon 
  ", 
  light 
  colored 
  augen-gneisses 
  

   believed 
  to 
  have 
  been 
  derived 
  from 
  porphyritic 
  granite 
  like 
  the 
  

   one 
  quarried 
  at 
  Horicon. 
  

  

  