﻿550 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  W 
  and 
  dipping 
  30 
  NE. 
  Over 
  it 
  after 
  a 
  concealed 
  interval 
  there 
  

   is 
  a 
  coarse 
  micaceous, 
  quartzose 
  gneiss, 
  with 
  nearly 
  the 
  same 
  

   strike 
  and 
  dip 
  viz 
  N 
  35 
  W 
  40 
  NE. 
  The 
  latter 
  contains 
  narrow 
  

   bands 
  of 
  hornblende 
  schist. 
  

  

  Minerva 
  is 
  one 
  of 
  the 
  richest 
  townships 
  in 
  crystalline 
  lime- 
  

   stones 
  of 
  any 
  and 
  together 
  with 
  Newcomb, 
  it 
  would 
  probably 
  

   yield 
  valuable 
  stratigraphic 
  results 
  if 
  mapped 
  in 
  detail. 
  

  

  Newcomb 
  

  

  A 
  partial 
  sketch 
  of 
  Newcomb 
  was 
  given 
  in 
  the 
  15th 
  annual 
  

   report 
  New 
  York 
  state 
  geologist, 
  p. 
  604. 
  At 
  the 
  time 
  that 
  it 
  was 
  

   prepared, 
  field 
  work 
  remained 
  to 
  be 
  done 
  in 
  the 
  northwestern 
  

   and 
  southwestern 
  portions 
  of 
  the 
  township. 
  That 
  has 
  now 
  been 
  

   performed 
  and 
  a 
  fairly 
  complete 
  outline 
  of 
  the 
  town 
  can 
  be 
  given. 
  

  

  Series 
  1. 
  The 
  gneisses 
  have 
  been 
  found 
  to 
  cover 
  all 
  the 
  north- 
  

   western 
  and 
  southwestern 
  portions 
  of 
  the 
  township. 
  They 
  are 
  

   greenish 
  varieties, 
  apparently 
  of 
  hornblendic 
  character 
  to 
  the 
  

   unaided 
  eye 
  and 
  present 
  in 
  almost 
  all 
  cases 
  the 
  features 
  of 
  the 
  

   syenitic 
  rocks, 
  often 
  referred 
  to 
  as 
  the 
  Whitehall 
  type. 
  They 
  

   vary 
  from 
  more 
  acidic 
  forms 
  with 
  free 
  quartz, 
  to 
  quite 
  basic 
  

   varieties, 
  with 
  abundant 
  dark 
  silicates 
  ^ 
  that 
  simulate 
  gabbros 
  

   and 
  that 
  have 
  troubled 
  us 
  greatly 
  as 
  to 
  their 
  identity 
  in 
  the 
  

   field. 
  Under 
  the 
  microscope 
  these 
  rocks 
  are 
  found 
  to 
  contain 
  

   orthoclase, 
  largely 
  microperthitic, 
  subordinate 
  plagioclase, 
  vary- 
  

   ing 
  amounts 
  of 
  brown 
  hornblende, 
  emerald 
  green 
  augite, 
  and 
  hy- 
  

   persthene, 
  sometimes 
  one 
  sometimes 
  another 
  predominating. 
  

   They 
  therefore 
  are 
  regarded 
  as 
  an 
  eruptive 
  rock, 
  it 
  may 
  be 
  of 
  

   series 
  3 
  that 
  has 
  been 
  foliated 
  by 
  dynamic 
  metamorphism. 
  

  

  Near 
  the 
  areas 
  of 
  crystalline 
  limestones, 
  biotitic 
  and 
  more 
  

   schistose 
  varieties 
  of 
  gneiss 
  are 
  met, 
  that 
  are 
  characteristic 
  of 
  

   this 
  series. 
  

  

  Series 
  2. 
  In 
  the 
  areas 
  more 
  recently 
  traversed, 
  no 
  new 
  lime 
  

   stone 
  outcrops 
  have 
  been 
  noted 
  but 
  there 
  may 
  be 
  some 
  small 
  

   ones 
  that 
  we 
  have 
  not 
  encountered. 
  

  

  Series 
  3. 
  Some 
  special 
  interest 
  has 
  attached' 
  to 
  the 
  delimita- 
  

   tions 
  of 
  the 
  anorthosiites 
  north 
  of 
  Newcomb 
  village, 
  and 
  it 
  is 
  

  

  