﻿A. 
  F. 
  Rogers 
  — 
  Miner 
  alogical 
  Notes. 
  

  

  365 
  

  

  tal 
  wanting. 
  Figs. 
  2 
  and 
  3 
  are 
  orthographic 
  projections 
  with 
  

   the 
  pinacoid 
  (010) 
  as 
  the 
  plane 
  of 
  projection. 
  

  

  2. 
  Calcite. 
  — 
  In 
  homogeneous 
  crystal 
  aggregates 
  composed 
  of 
  

   individuals 
  in 
  parallel 
  position 
  the 
  individuals 
  are 
  usually 
  sim- 
  

   ilar 
  in 
  habit. 
  Those 
  in 
  which 
  the 
  individuals 
  are 
  different 
  in 
  

   habit 
  seem 
  to 
  be 
  of 
  rather 
  rare 
  occurrence. 
  Oar 
  general 
  

   mineralogical 
  literature 
  contains 
  descriptions 
  and 
  figures 
  of 
  but 
  

   few 
  such. 
  An 
  aggregate 
  of 
  this 
  kind 
  composed 
  of 
  calcite 
  crys- 
  

   tals 
  is 
  represented 
  in 
  fig. 
  4, 
  which 
  is 
  an 
  orthographic 
  projec- 
  

   tion 
  with 
  the 
  basal 
  pinacoid 
  (0001) 
  as 
  the 
  plane 
  of 
  projection. 
  

   These 
  specimens 
  were 
  collected 
  by 
  the 
  writer 
  (where 
  they 
  

   occur 
  in 
  cavities 
  in 
  limestone) 
  at 
  Argentine, 
  Kansas. 
  The 
  

   crystal 
  host, 
  as 
  it 
  may 
  be 
  called, 
  is 
  light 
  brown 
  in 
  color 
  and 
  ex- 
  

   hibits 
  the 
  following 
  forms, 
  r 
  (1011)R 
  ; 
  /(0221)-2. 
  Truncating 
  

   the 
  polar 
  edges 
  of 
  r 
  are 
  pseudo-rhombohedral 
  faces 
  of 
  the 
  

  

  negative 
  rhombohedron 
  — 
  -J, 
  formed 
  by 
  oscillatory 
  combination 
  

   of 
  the 
  latter 
  form 
  with 
  the 
  positive 
  unit 
  rhombohedron. 
  

   On 
  each 
  of 
  the 
  r 
  faces 
  is 
  placed 
  a 
  flat 
  colorless 
  calcite 
  crystal 
  

   with 
  the 
  forms, 
  ^(1011); 
  #(0112) 
  and 
  an 
  undetermined 
  scaleno- 
  

   hedron. 
  The 
  unit 
  rhombohedron 
  is 
  the 
  predominant 
  form, 
  

   while 
  the 
  negative 
  rhombohedron 
  and 
  the 
  scalenohedron 
  which 
  

   are 
  not 
  shown 
  in 
  the 
  drawing, 
  appear 
  as 
  very 
  narrow 
  faces 
  the 
  

   latter 
  bevelling 
  the 
  basal 
  edges 
  of 
  r. 
  The 
  superimposed 
  crys- 
  

   tals 
  are 
  distinct 
  crystals 
  and 
  may 
  easily 
  be 
  removed 
  from 
  their 
  

   host 
  without 
  damage 
  to 
  either. 
  

  

  Another 
  parallel 
  aggregate 
  composed 
  of 
  calcite 
  crystals 
  of 
  

   different 
  habit 
  was 
  found 
  in 
  limestone 
  at 
  Kansas 
  City, 
  Mo. 
  

   On 
  the 
  top 
  of 
  the 
  scalenohedron 
  v 
  (2131) 
  with 
  its 
  shorter 
  polar 
  

   edges 
  truncated 
  by 
  /(0221) 
  is 
  placed 
  a 
  unit 
  rhombohedron 
  of 
  

   the 
  same 
  mineral, 
  their 
  apices 
  coinciding. 
  The 
  scalenohedron 
  

   is 
  covered 
  with 
  a 
  thin 
  brownish 
  film 
  while 
  the 
  rhombohedron 
  

   is 
  colorless 
  and 
  perfectly 
  transparent. 
  

  

  3. 
  Calcite. 
  — 
  Occurring 
  in 
  chalk 
  in 
  the 
  western 
  part 
  of 
  

   Kansas 
  along 
  the 
  Smoky 
  Hill 
  river 
  in 
  Logan, 
  Gove 
  and 
  Trego 
  

   Counties, 
  are 
  veins 
  of 
  calcite 
  in 
  which 
  are 
  cavities 
  lined 
  with 
  

  

  