﻿Rocks, 
  in 
  Littleton, 
  New 
  Hampshire. 
  

  

  239 
  

  

  Per 
  cent 
  

   quartz. 
  

  

  Per 
  cent 
  

   feldspar. 
  

  

  Per 
  cent 
  

   calcite. 
  

  

  Per 
  cent 
  iron- 
  

   bearing 
  silicates. 
  

  

  Per 
  cent 
  

   total 
  iron 
  

   silicates. 
  

  

  Total. 
  

  

  Southern 
  

   phase. 
  

  

  Sp. 
  106 
  

  

  27-08 
  

  

  52-93 
  

  

  

  

  Chlorite 
  : 
  

  

  19-97 
  

  

  19-97 
  

  

  99-98 
  

  

  Sp. 
  302 
  

  

  18-42 
  

  

  61-79 
  

  

  

  

  Chlorite 
  : 
  

   Epidote 
  : 
  

  

  1959 
  

   0-18 
  

  

  19-77 
  

  

  99-98 
  

  

  Sp. 
  245 
  

  

  26-20 
  

  

  46-20 
  

  

  7-05 
  

  

  Chlorite 
  : 
  

  

  20-54 
  

  

  20-54 
  

  

  99-99 
  

  

  Northern 
  

   phase. 
  

  

  

  

  

  

  

  

  Sp. 
  448 
  

  

  21-16 
  

  

  57-44 
  

  

  •36 
  

  

  Chlorite: 
  1'89 
  

   Epidote 
  : 
  4*84 
  

   Hornblende: 
  14-30 
  

  

  21-03 
  

  

  99-99 
  

  

  Sp. 
  447 
  

  

  14-98 
  

  

  61-07 
  

  

  •17 
  

  

  Chlorite 
  : 
  3 
  11 
  

   Epidote 
  : 
  3 
  -99 
  

   Hornblende: 
  16 
  "66 
  

  

  23-76 
  

  

  99-98 
  

  

  Average 
  for 
  southern 
  phase 
  

  

  23-9 
  

  

  5364 
  

  

  2-35 
  

  

  Chlorite 
  : 
  20'02 
  

   Epidote 
  : 
  -06 
  

  

  99- 
  

  

  Average 
  for 
  northern 
  phase: 
  

  

  18-07 
  

  

  59-25 
  

  

  •26 
  

  

  Chlorite 
  : 
  2 
  -50 
  

   Epidote 
  : 
  4-41 
  

  

  Hornblende: 
  15 
  '48 
  

  

  22-39 
  99-97 
  

  

  The 
  above 
  table 
  shows 
  that 
  the 
  northern 
  phase 
  has 
  a 
  lower 
  

   percentage 
  of 
  free 
  quartz 
  than 
  the 
  southern 
  phase, 
  a 
  higher 
  

   percentage 
  of 
  feldspar, 
  and 
  a 
  slightly 
  greater 
  percentage 
  of 
  

   iron-bearing 
  silicates, 
  although 
  hornblende 
  comprises 
  the 
  larger 
  

   proportion 
  of 
  these 
  silicates 
  in 
  the 
  northern 
  type, 
  and 
  chlorite 
  

   in 
  the 
  southern. 
  Hornblende 
  is 
  quite 
  wanting 
  in 
  the 
  southern 
  

   facies. 
  These 
  facts 
  suggest 
  a 
  certain 
  amount 
  of 
  magmatic 
  dif- 
  

   ferentiation 
  in 
  the 
  original 
  granite 
  magma, 
  either 
  by 
  an 
  

   increase 
  in 
  acidity 
  toward 
  the 
  southern 
  boundary 
  or 
  by 
  an 
  

   increase 
  in 
  basicity 
  toward 
  the 
  northern 
  boundary. 
  

  

  Intrusive 
  contact 
  with 
  the 
  Lyman 
  schists. 
  — 
  We 
  can 
  dis- 
  

   cover 
  in 
  the 
  literature 
  no 
  mention 
  of 
  the 
  relation 
  of 
  the 
  Fitch 
  

   Hill 
  granite 
  gneiss 
  to 
  the 
  Lyman 
  schists. 
  Although 
  the 
  con- 
  

   tact 
  is 
  actually 
  exposed 
  in 
  many 
  places, 
  it 
  is 
  so 
  obscure 
  on 
  

   account 
  of 
  metamorphism 
  and 
  weathering 
  that 
  its 
  study 
  

   requires 
  more 
  detailed 
  search 
  than 
  was 
  possible 
  under 
  the 
  con- 
  

   ditions 
  of 
  the 
  earlier 
  geological 
  surveys. 
  

  

  When 
  carefully 
  examined, 
  this 
  contact 
  is 
  seen 
  to 
  be 
  very 
  

   irregular. 
  The 
  granite 
  gneiss 
  projects 
  into 
  the 
  schists 
  in 
  the 
  

   form 
  of 
  blunt 
  apophyses 
  or 
  as 
  short, 
  narrow 
  dikes. 
  Most 
  of 
  

   these 
  intrusive 
  tongues 
  are 
  of 
  fine 
  grain 
  ; 
  but 
  a 
  few 
  are 
  peg- 
  

   matitic, 
  sometimes 
  with 
  quartz 
  and 
  feldspar 
  crystals 
  an 
  inch 
  or 
  

   two 
  across. 
  Angular 
  fragments 
  of 
  the 
  schist 
  are 
  occasionally 
  

   seen 
  entirely 
  included 
  within 
  the 
  gneiss. 
  Add 
  to 
  these 
  state- 
  

   ments 
  the 
  fact 
  that 
  the 
  gneiss 
  usually 
  grows 
  finer 
  toward 
  the 
  

  

  