﻿46 
  J. 
  Stanley 
  -Brown 
  — 
  Bernardinite 
  : 
  Is 
  it 
  a 
  

  

  In 
  some 
  of 
  the 
  more 
  irregular 
  cavities 
  of 
  the 
  rock, 
  at 
  Glade 
  

   Creek, 
  there 
  are 
  accumulations 
  of 
  sanidine 
  crystals 
  of 
  very 
  

   small 
  size. 
  Occasionally 
  they 
  exhibit 
  a 
  blue 
  iridescence, 
  and 
  

   when 
  magnified 
  are 
  seen 
  to 
  have 
  the 
  same 
  crystal 
  habit 
  as 
  

   those 
  in 
  the 
  lithoidite 
  of 
  Obsidian 
  Cliff,* 
  that 
  is, 
  they 
  are 
  thin 
  

   tablets 
  parallel 
  to 
  the 
  basal 
  plane, 
  with 
  the 
  clinopinacoid, 
  prism 
  

   and 
  two 
  orthodomes 
  less 
  highly 
  developed. 
  The 
  chemical 
  

   analysis 
  of 
  these 
  uncommon 
  sanidines 
  from 
  Obsidian 
  Cliff 
  

   showed 
  the 
  presence 
  of 
  one 
  molecule 
  of 
  soda 
  to 
  one 
  of 
  potash. 
  

   In 
  some 
  of 
  the 
  hollow 
  spherulites 
  there 
  are 
  very 
  small 
  crystals 
  

   of 
  hornblende 
  about 
  \ 
  mm 
  long. 
  They 
  form 
  stout 
  prisms 
  with 
  

   brilliant 
  faces, 
  and 
  appear 
  to 
  be 
  terminated 
  by 
  the 
  basal 
  plane 
  

   and 
  unit 
  pyramid. 
  In 
  thin 
  section 
  they 
  are 
  brown. 
  They 
  are 
  

   not 
  found 
  in 
  most 
  of 
  the 
  cavities. 
  Biotite 
  is 
  also 
  observed, 
  in 
  

   a 
  few 
  cases, 
  in 
  very 
  small 
  particles 
  built 
  up 
  of 
  thin 
  hexagonal 
  

   crystals 
  with 
  parallel 
  orientation. 
  They 
  yield 
  an 
  almost 
  uni- 
  

   axial 
  negative 
  interference 
  figure 
  between 
  crossed 
  nicols. 
  

   Both 
  the 
  hornblende 
  and 
  biotite 
  occur 
  sparingly 
  in 
  small 
  

   crystals 
  within 
  the 
  groundmass 
  of 
  the 
  rock. 
  These 
  minerals 
  

   are 
  not 
  found 
  in 
  the 
  same 
  cavities 
  with 
  fayalite. 
  

  

  In 
  conclusion, 
  we 
  find 
  that 
  in 
  the 
  rhyolite 
  of 
  Glade 
  Creek, 
  

   as 
  in 
  the 
  obsidian 
  of 
  Obsidian 
  Cliff, 
  fayalite 
  occurs 
  in 
  associ- 
  

   ation 
  with 
  abundant 
  quartz, 
  as 
  the 
  result 
  of 
  the 
  mineralizing 
  

   action 
  of 
  vapors 
  in 
  the 
  cooling 
  acid 
  lava. 
  The 
  quartz 
  in 
  

   both 
  localities 
  has 
  a 
  peculiar 
  development, 
  remarkable 
  alike 
  

   for 
  its 
  simplicity, 
  rarity 
  and 
  perfection. 
  These 
  minerals 
  are 
  

   accompanied 
  by 
  an 
  uncommon 
  form 
  of 
  sanidine, 
  and 
  by 
  tridy- 
  

   mite. 
  Moreover 
  in 
  certain 
  hollow 
  spherulites 
  the 
  fayalite 
  is 
  

   wanting, 
  and 
  in 
  its 
  place 
  are 
  hornblende 
  and 
  biotite. 
  

  

  Aet. 
  VI. 
  — 
  Bernardinite 
  : 
  Is 
  it 
  a 
  Mineral 
  or 
  a 
  Fungus 
  f\ 
  

   by 
  Joseph 
  Stanley- 
  Brown. 
  

  

  Twelve 
  years 
  ago 
  Prof. 
  J. 
  M. 
  Stillman 
  announced 
  through 
  

   this 
  Journal 
  % 
  his 
  discovery 
  of 
  " 
  a' 
  new 
  mineral 
  resin 
  from 
  San 
  

   Bernardino 
  Co., 
  Cal.," 
  and 
  proposed 
  for 
  it 
  the 
  name 
  "Bernard- 
  

   inite." 
  The 
  specimens 
  were 
  sent 
  to 
  him 
  by 
  farmers 
  who, 
  find- 
  

   ing 
  them 
  among 
  rocks, 
  supposed 
  them 
  to 
  be 
  derived 
  from 
  veins. 
  

  

  While 
  engaged 
  in 
  geological 
  work 
  in 
  northeastern 
  California 
  

   during 
  the 
  summer 
  and 
  fall 
  of 
  1890, 
  Mr. 
  A. 
  B. 
  Frost, 
  of 
  Susan- 
  

   ville, 
  called 
  my 
  attention 
  to 
  the 
  occurrence 
  of 
  bernardinite 
  near 
  

   Eagle 
  Lake. 
  Search 
  for 
  the 
  mineral 
  was 
  unrewarded 
  for 
  the 
  

  

  * 
  L. 
  c. 
  p. 
  267, 
  figs. 
  51 
  and 
  52. 
  

  

  f 
  Abstract 
  of 
  a 
  paper 
  read 
  before 
  the 
  Washington 
  Phil. 
  Soc., 
  Mar. 
  14, 
  1890 
  r 
  

   and 
  now 
  printed 
  by 
  permission 
  of 
  the 
  Director 
  of 
  the 
  U. 
  S. 
  Geol. 
  Survey. 
  

   \ 
  This 
  Jour., 
  vol. 
  xviii, 
  page 
  57. 
  

  

  