﻿56 
  TWENTY-FIRST 
  REPORT 
  ON 
  THE 
  STATE 
  CABINET. 
  

  

  Lake, 
  possibly 
  belongs 
  to 
  Laurentian 
  rocks 
  (Geol. 
  Can., 
  page 
  492), 
  

   These 
  veins, 
  from 
  their 
  constituent 
  minerals, 
  are 
  generally 
  de- 
  

   scribed 
  as 
  granitic, 
  but 
  are 
  not 
  to 
  be 
  confounded 
  with 
  injected 
  

   granite 
  dykes, 
  since 
  they 
  are 
  doubtless 
  true 
  veins, 
  like 
  those 
  of 
  

   the 
  first 
  class, 
  filled 
  by 
  the 
  gradual 
  deposition 
  of 
  matters 
  from 
  

   aqueous 
  solutions. 
  These 
  granitic 
  veins, 
  unlike 
  those 
  of 
  the 
  pre- 
  

   ceding 
  class, 
  have 
  not 
  been 
  observed 
  to 
  intersect 
  the 
  Silurian 
  

   rocks, 
  and 
  are 
  probably 
  of 
  greater 
  antiquity 
  than 
  they. 
  As 
  will 
  

   hereafter 
  be 
  shown, 
  they 
  cannot 
  be 
  distinguished 
  from 
  the 
  veins 
  

   of 
  the 
  third 
  class, 
  into 
  which 
  they 
  pass 
  by 
  insensible 
  degrees. 
  

  

  3. 
  In 
  the 
  third 
  class 
  were 
  included, 
  in 
  the 
  Geology 
  of 
  Canada, 
  

   those 
  veins 
  which 
  appear 
  to 
  be 
  more 
  nearly 
  related 
  to 
  the 
  lime- 
  

   stone 
  groups, 
  with 
  which 
  the}^ 
  are 
  generally 
  associated, 
  and 
  with 
  

   the 
  characteristic 
  minerals 
  of 
  which 
  they 
  are 
  filled. 
  These 
  veins 
  are 
  

   extremely 
  numerous, 
  and 
  exhibit, 
  within 
  certain 
  limits, 
  remarkable 
  

   variations 
  in 
  mineralogical 
  characters. 
  The 
  most 
  important 
  ele- 
  

   ments 
  of 
  these 
  veins 
  are 
  calcite, 
  quartz, 
  orthoclase, 
  phlogopite, 
  

   pyroxene, 
  apatite 
  and 
  graphite, 
  of 
  which 
  some 
  one 
  or 
  more 
  will 
  

   be 
  found 
  to 
  prevail 
  ; 
  but 
  they 
  may 
  contain, 
  besides, 
  numerous 
  

   other 
  species, 
  including 
  nearly 
  every 
  one 
  to 
  be 
  met 
  with 
  in 
  the 
  

   limestones, 
  and 
  in 
  their 
  accompanying 
  pyroxenic 
  and 
  gneissic 
  

   rocks. 
  Veins 
  of 
  the 
  present 
  class 
  are 
  found 
  traversing 
  all 
  these 
  

   strata 
  ; 
  they 
  are 
  most 
  frequently 
  vertical 
  in 
  attitude, 
  and 
  generally 
  

   cut 
  the 
  beds 
  at 
  right 
  angles, 
  though 
  to 
  this 
  many 
  exceptions 
  may 
  

   be 
  cited. 
  They 
  exhibit, 
  within 
  certain 
  limits, 
  great 
  variations 
  in 
  

   their 
  mineralogical 
  characters, 
  not 
  only 
  in 
  different 
  veins, 
  but 
  in 
  

   different 
  parts 
  of 
  the 
  same 
  vein. 
  Thus, 
  in 
  some 
  cases, 
  pyroxene 
  

   is 
  the 
  predominant 
  mineral, 
  and 
  other 
  species 
  are 
  present 
  only 
  in 
  

   small 
  quantities. 
  At 
  other 
  times, 
  orthoclase, 
  apatite, 
  or 
  magne- 
  

   sian 
  mica 
  makes 
  up 
  the 
  great 
  mass 
  of 
  the 
  vein, 
  and 
  in 
  other 
  cases, 
  

   calcareous 
  spar. 
  It 
  is 
  the 
  veins 
  of 
  this 
  latter 
  mineral 
  which 
  have 
  

   doubtless 
  been, 
  by 
  Emmons 
  and 
  other 
  observers, 
  described 
  as 
  

   intrusive 
  veins 
  of 
  crystalline 
  limestone. 
  Having 
  generally 
  a 
  solidly 
  

   crystalline 
  lamellar 
  structure, 
  very 
  unlike 
  the 
  more 
  or 
  less 
  cav- 
  

   ernous 
  calcareous 
  veinstones 
  of 
  the 
  first 
  class, 
  and 
  sometimes 
  

   holding 
  only 
  sparsely 
  disseminated 
  crystals 
  of 
  one 
  or 
  more 
  of 
  the 
  

   minerals 
  which 
  are 
  common 
  to 
  the 
  stratified 
  limestones, 
  such 
  as 
  

   pyroxene, 
  mica, 
  or 
  apatite, 
  the 
  observer 
  will 
  often 
  find 
  it 
  difficult 
  

   to 
  determine 
  whether 
  a 
  detached 
  mass, 
  or 
  an 
  imperfectly 
  dis- 
  

   played 
  out-crop 
  of 
  crystalline 
  limestone, 
  belongs 
  to 
  a 
  bed 
  or 
  a 
  

   vein. 
  When, 
  however, 
  it 
  is 
  possible 
  to 
  make 
  a 
  thorough 
  exami- 
  

  

  