﻿80 
  TWENTY-FIRST 
  REPORT 
  ON 
  THE 
  STATE 
  CABINET. 
  

  

  The 
  occurrence 
  of 
  beds 
  of 
  this 
  compound, 
  more 
  or 
  less 
  pure 
  

   (dyssyntribite 
  and 
  parophite), 
  as 
  a 
  massive 
  or 
  schistose 
  rock, 
  alike 
  

   in 
  the 
  Lauren 
  tian 
  and 
  Silurian 
  series, 
  leads 
  us 
  to 
  assign 
  to 
  it 
  a 
  

   rank 
  and 
  an 
  origin 
  am.mg 
  such 
  rocks 
  as 
  serpentine, 
  steatite, 
  

   pyroxene, 
  chlorite, 
  glauconite 
  and 
  epiclote, 
  all 
  of 
  which 
  silicates, 
  

   and 
  many 
  others, 
  have 
  been 
  in 
  most 
  cases 
  deposited 
  as 
  aqueous 
  

   sediments 
  generated 
  by 
  chemical 
  reactions 
  at 
  the 
  earth's 
  surface, 
  

   and 
  in 
  many 
  cases 
  subsequently 
  modified 
  by 
  crystallization, 
  or 
  

   molecular 
  re-arrangement 
  (Geol. 
  Can., 
  page 
  581.) 
  

  

  As 
  I 
  have 
  elsewhere 
  remarked, 
  although 
  sparry 
  in 
  structure, 
  

   gieseckite 
  and 
  wilsonite 
  have 
  very 
  nearly 
  the 
  chemical 
  composi- 
  

   tion 
  of 
  the 
  hydrous 
  potash-mica, 
  margarodite. 
  In 
  like 
  manner 
  the 
  

   sparry 
  silicates, 
  pyrallolite 
  and 
  loganite, 
  correspond 
  to 
  the 
  foliated 
  

   species, 
  talc 
  and 
  pyrosclerite, 
  of 
  which 
  they 
  have 
  the 
  elementary 
  

   composition, 
  although 
  differing 
  entirely 
  in 
  structure 
  {Ibid, 
  page 
  

   492:). 
  

  

  Loganite. 
  — 
  This 
  prismatic 
  hydrous 
  species, 
  which 
  I 
  first 
  de- 
  

   scribed 
  in 
  1848, 
  has 
  recently 
  acquired 
  a 
  new 
  interest. 
  It 
  occurs 
  

   in 
  several 
  places 
  as 
  a 
  veinstone, 
  in 
  one 
  case 
  filling 
  the 
  central 
  por- 
  

   tion 
  of 
  a 
  vein 
  of 
  apatite, 
  and 
  inclosing 
  calcite 
  and 
  sphene; 
  and 
  in 
  

   another, 
  in 
  considerable 
  masses, 
  w 
  T 
  ith 
  large 
  crystals 
  of 
  mica, 
  im- 
  

   bedded 
  in 
  a 
  great 
  vein 
  of 
  pyroxene. 
  Evidence 
  of 
  its 
  occurrence 
  

   as 
  a 
  sedimentary 
  mineral 
  is 
  afforded 
  by 
  the 
  fact 
  that 
  in 
  one 
  locality 
  

   it 
  forms 
  the 
  enclosing 
  and 
  filling 
  material 
  of 
  the 
  Eozoon. 
  

  

  [This 
  species, 
  numerous 
  analyses 
  of 
  which 
  will 
  be 
  found 
  in 
  the 
  

   Geology 
  of 
  Canada, 
  page 
  491, 
  has 
  been 
  by 
  Dana 
  (Mineralogy, 
  4th 
  

   edition) 
  referred 
  to 
  pyrosclerite, 
  which 
  he 
  however 
  described 
  as 
  

   possessing 
  an 
  eminent 
  basal 
  cleavage, 
  and 
  in 
  fact 
  identical 
  with 
  

   the 
  foliated 
  micaceous 
  minerals 
  kaemmererite 
  and 
  vermiculite. 
  I 
  

   have 
  maintained 
  the 
  distinctness 
  of 
  loganite 
  from 
  these, 
  first, 
  from 
  

   the 
  greater 
  amount 
  of 
  water 
  in 
  its 
  composition, 
  and, 
  secondly, 
  

   from 
  the 
  entire 
  absence 
  of 
  foliated 
  or 
  micaceous 
  structure. 
  Speci- 
  

   mens 
  declared 
  to 
  be 
  the 
  original 
  pyrosclerite 
  from 
  Elba, 
  which 
  I 
  

   have 
  since 
  examined, 
  have, 
  however, 
  a 
  sparry 
  aspect, 
  and 
  a 
  cleavage 
  

   resembling 
  that 
  of 
  pyroxene 
  and 
  loganite. 
  The 
  difference 
  in 
  com- 
  

   position 
  between 
  loganite 
  and 
  pyrosclerite 
  still 
  remains 
  to 
  be 
  got 
  

   over; 
  but 
  if 
  these 
  two 
  minerals 
  are 
  to 
  be 
  identified, 
  neither 
  of 
  them 
  

   can 
  be 
  confounded 
  with 
  kaemmererite 
  or 
  vermiculite, 
  from 
  which 
  

   they 
  differ 
  as 
  pyrallolite 
  does 
  from 
  talc] 
  

  

  In 
  the 
  Geology 
  of 
  Canada, 
  page 
  490, 
  attention 
  has 
  been 
  called 
  

  

  