﻿326 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  dimensions 
  are 
  as 
  follows: 
  21 
  cm. 
  by 
  25 
  cm. 
  by 
  12 
  cm.; 
  weight, 
  

   10.10 
  kilograms. 
  

  

  As 
  mentioned 
  above, 
  the 
  stone 
  is 
  so 
  dense 
  and 
  fine-grained 
  that 
  

   nothing 
  of 
  its 
  mineral 
  nature 
  can 
  be 
  learned 
  from 
  an 
  examination 
  of 
  

   a 
  broken 
  surface 
  by 
  the 
  unaided 
  eye. 
  A 
  sawni 
  and 
  polished 
  surface 
  

   is, 
  however, 
  abundantly 
  specked 
  with 
  small 
  metallic 
  points 
  and 
  

   numerous 
  chondrules. 
  In 
  the 
  main 
  the 
  distribution 
  of 
  the 
  metallic 
  

   constituents 
  is 
  fairly 
  even, 
  but 
  diversified 
  by 
  stringei-s 
  of 
  either 
  metal 
  

   alone 
  or 
  metal 
  and 
  metallic 
  sulphide 
  together, 
  which 
  seem 
  for 
  the 
  

   most 
  part 
  to 
  have 
  a 
  general 
  trend 
  ; 
  that 
  is, 
  their 
  longer 
  axes 
  show 
  a 
  

   tendency 
  toward 
  parallelism 
  as 
  though 
  developed 
  along 
  lines 
  of 
  weak- 
  

   ness 
  caused 
  by 
  shearing. 
  (PI. 
  55, 
  fig. 
  2.) 
  

  

  In 
  the 
  thin 
  section 
  the 
  meteoric 
  nature 
  of 
  the 
  stone 
  is 
  at 
  once 
  

   apparent. 
  Everywhere 
  it 
  presents 
  a 
  dense 
  aggregate 
  of 
  small 
  

   chondrules, 
  sometimes 
  mere 
  fragments 
  or 
  again 
  remarkable 
  for 
  their 
  

   sharp 
  and 
  circular 
  outline, 
  imbedded 
  in 
  a 
  fragmental 
  and 
  tuff-like 
  

   gi-ound. 
  In 
  its 
  mineral 
  composition 
  the 
  stone 
  presents 
  nothing 
  new; 
  

   olivine, 
  orthorhombic 
  and 
  monoclinic 
  pyroxenes 
  and 
  fragmentary 
  

   plagioclase 
  feldspars, 
  together 
  with 
  metallic 
  iron 
  and 
  iron 
  sulphides, 
  

   make 
  up 
  the 
  entire 
  recognizable 
  constituents. 
  As 
  noted 
  later 
  (p. 
  330) 
  , 
  

   there 
  seems 
  a 
  possibility 
  of 
  the 
  one-time 
  presence 
  of 
  oldhamite. 
  

  

  The 
  stone 
  is 
  of 
  interest, 
  however, 
  from 
  the 
  diversity 
  of 
  the 
  chondritic 
  

   forms 
  which 
  it 
  carries. 
  There 
  are 
  the 
  common 
  monosomatic, 
  barred, 
  

   grate-like 
  and 
  porphyi-itic 
  forms 
  composed 
  wholly 
  of 
  olivine; 
  the 
  

   radiating 
  fan-like 
  forms 
  composed 
  of 
  enstatite; 
  also 
  porphyritic 
  forms 
  

   composed 
  of 
  enstatite 
  in 
  a 
  smoky 
  or 
  felt-like 
  glass, 
  and 
  still 
  further 
  

   chondrules 
  composed 
  wholly 
  of 
  twinned, 
  monoclinic 
  pyroxenes. 
  These 
  

   last 
  sometimes 
  display 
  a 
  structure 
  which 
  is 
  new 
  to 
  me, 
  the 
  outer 
  rim 
  

   consisting 
  of 
  crystals 
  somewhat 
  curved 
  to 
  conform 
  to 
  the 
  outline 
  of 
  

   the 
  chondrule 
  and 
  elongated 
  in 
  the 
  direction 
  of 
  their 
  vertical 
  axes, 
  

   so 
  that 
  sections 
  in 
  other 
  than 
  the 
  orthopinacoid 
  zone 
  show 
  more 
  or 
  

   less 
  distinct 
  striations. 
  Interiorly 
  this 
  type 
  of 
  chondrule 
  is 
  a 
  mass 
  

   of 
  imperfectly 
  outlined 
  granules 
  some 
  of 
  which 
  show 
  twin 
  striae, 
  but 
  

   the 
  structure 
  as 
  a 
  rule 
  is 
  very 
  obscure 
  and 
  no 
  attempt 
  has 
  been 
  made 
  

   to 
  reproduce 
  it 
  in 
  detail 
  by 
  photograph 
  or 
  drawing. 
  An 
  occasional 
  

   form 
  is 
  met 
  with 
  in 
  which 
  the 
  interior 
  is 
  wholly 
  of 
  a 
  yellowish 
  glass 
  

   while 
  the 
  rim 
  is 
  of 
  a 
  fibrous 
  pyroxenic 
  ( 
  ?) 
  material 
  radiating 
  fi-om 
  a 
  

   common 
  center. 
  Several 
  minute 
  and 
  very 
  nearly 
  circular 
  chondrules 
  

   were 
  noted, 
  like 
  a 
  slightly 
  bro^vnish, 
  wine-tinted 
  homogeneous 
  glass 
  

   traversed 
  by 
  numerous 
  cracks 
  into 
  which 
  secondary 
  iron 
  oxides 
  had 
  

   penetrated. 
  Between 
  crossed 
  nicols 
  this 
  glass 
  proves 
  not 
  absolutely 
  

   isotropic, 
  but 
  a 
  portion 
  remains 
  light, 
  the 
  dark 
  cloud 
  sweeping 
  over 
  

   it 
  as 
  the 
  stage 
  is 
  revolved, 
  in 
  a 
  manner 
  to 
  suggest 
  a 
  condition 
  of 
  

   mechanical 
  str&ss. 
  Occasional 
  faintly 
  bluish-gray 
  forms 
  occur 
  wliich 
  

   are 
  apparently 
  comparable 
  with 
  those 
  described 
  by 
  Tschermak 
  in 
  the 
  

   stone 
  of 
  Tipperary. 
  

  

  