﻿86 
  

  

  Thirtieth 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  the 
  anorthosite 
  rocks 
  composing 
  the 
  Norian 
  System 
  in 
  Canada, 
  

   northern 
  New 
  York, 
  and 
  elsewhere. 
  It 
  will 
  be 
  so 
  employed 
  in 
  

   the 
  subsequent 
  portions 
  of 
  this 
  article, 
  the 
  names 
  hypersthenic- 
  

   hornblendic, 
  or 
  pyroxenic-norite, 
  being 
  applied 
  to 
  rocks 
  in 
  

   which 
  these 
  secondary 
  ingredients 
  occur, 
  rather 
  than 
  hyperite, 
  

   diorite 
  or 
  dolerite 
  into 
  which 
  such 
  rock 
  combinations 
  may 
  pass, 
  

   but 
  from 
  which 
  they 
  are 
  to 
  be 
  distinguished 
  by 
  the 
  stratified 
  

   and 
  concretionary 
  structure 
  of 
  the 
  constituent 
  minerals. 
  

  

  II. 
  Descriptive 
  Lithology. 
  

  

  The 
  rocks, 
  69 
  in 
  number, 
  were 
  all 
  collected 
  in 
  the 
  county 
  of 
  

   Essex, 
  and 
  most 
  in 
  the 
  valley 
  and 
  township 
  of 
  Keene. 
  Very 
  

   many 
  others, 
  presenting 
  nothing 
  in 
  their 
  characters 
  distinctive 
  

   from 
  the 
  69 
  mentioned, 
  were 
  excluded 
  from 
  this 
  description. 
  

   The 
  design 
  was 
  not 
  to 
  attempt 
  the 
  study 
  of 
  the 
  stratigraphy 
  of 
  

   the 
  Adirondacks 
  at 
  the 
  present 
  time. 
  It 
  was 
  rather, 
  as 
  prelim- 
  

   inary 
  to 
  such 
  an 
  undertaking, 
  to 
  analyze 
  and 
  classify 
  with 
  pre- 
  

   cision 
  as 
  many 
  varieties 
  of 
  Adirondack 
  rock-masses 
  as 
  possible, 
  

   in 
  order 
  to 
  compare 
  the 
  rocks 
  of 
  one 
  and 
  different 
  localities, 
  

   and, 
  in 
  case 
  of 
  erratic 
  boulders, 
  to 
  ascertain 
  their 
  origin 
  and 
  

   mode 
  of 
  distribution. 
  During 
  the 
  course 
  of 
  last 
  summer, 
  the 
  

   specific 
  gravities 
  of 
  44 
  of 
  these 
  specimens 
  were 
  determined 
  by 
  

   Mr. 
  Brown 
  Ayres, 
  one 
  of 
  the 
  students 
  of 
  the 
  Stevens 
  Institute 
  

   of 
  Technology, 
  who 
  was 
  also 
  my 
  field-assistant. 
  It 
  will 
  be 
  

   most 
  convenient, 
  to 
  study 
  these 
  varieties 
  in 
  the 
  ascending 
  order 
  

   of 
  their 
  specific 
  gravities, 
  as 
  they 
  are 
  presented 
  in 
  the 
  following 
  

  

  table 
  : 
  

  

  Table 
  of 
  Specific 
  Gravities 
  of 
  Noriles. 
  

  

  1... 
  

  

  2.67 
  

  

  16, 
  

  

  2.81 
  

  

  31 
  

  

  3.09 
  

  

  2 
  .. 
  

  

  2.68 
  

  

  17 
  

  

  2.82 
  

  

  32 
  

  

  3.097 
  

  

  3... 
  

  

  2.69 
  

  

  18 
  

  

  2.82 
  

  

  33 
  

  

  3.097 
  

  

  4... 
  

  

  2.70 
  

  

  19 
  

  

  2.86 
  

  

  34 
  

  

  3.10 
  

  

  5 
  

  

  2.71* 
  

  

  20 
  

  

  2.89 
  

  

  35 
  

  

  3.11 
  

  

  6... 
  

  

  2.71 
  

  

  21 
  

  

  2.89* 
  

  

  36 
  

  

  3.11 
  

  

  7... 
  

  

  2.71 
  

  

  22 
  

  

  2.89 
  

  

  37 
  

  

  3.13 
  

  

  8... 
  

  

  2.72 
  

  

  23 
  

  

  2.91 
  

  

  38 
  

  

  3.15 
  

  

  9... 
  

  

  2.74 
  

  

  24 
  

  

  2.96 
  

  

  39 
  

  

  3.17 
  

  

  10... 
  

  

  2.74 
  

  

  25 
  

  

  2.96 
  

  

  40 
  

  

  3.21 
  

  

  11... 
  

  

  2.76 
  

  

  26 
  

  

  2.97 
  

  

  41 
  

  

  3.23 
  

  

  12 
  . 
  

  

  2.77 
  

  

  27 
  

  

  2.99 
  

  

  42 
  

  

  3.24 
  

  

  13... 
  

  

  2.77 
  

  

  28 
  

  

  3.00 
  

  

  43 
  

  

  3.386 
  f 
  

  

  14... 
  

  

  2.77 
  

  

  29 
  

  

  3.04 
  

  

  44 
  

  

  3.459 
  X 
  

  

  15... 
  

  

  2.79 
  

  

  30 
  

  

  3.062 
  

  

  

  

  

  * 
  Analyzed. 
  

  

  

  f 
  Diallage. 
  

  

  X 
  Hypersthene. 
  

  

  

  