﻿582 
  

  

  PKOE. 
  C. 
  LAPWOKTH 
  ON 
  THE 
  GIKVAN 
  SUCCESSION. 
  

  

  s.w. 
  

  

  Crazqhead 
  MM- 
  

  

  Fig. 
  13. 
  — 
  Section 
  of 
  Craighead 
  Quarries. 
  

  

  N.E. 
  

  

  ' 
  West 
  Quarry. 
  

  

  £ojC 
  Quarry 
  

  

  

  Stinchar 
  Limestone 
  Group. 
  

   Ab 
  4 
  . 
  Didymograp>tus-z<me> 
  : 
  — 
  

  

  (c) 
  Shivery 
  shales 
  with 
  Encrinurus, 
  Ampyx, 
  Leptana, 
  &c. 
  

  

  (b) 
  Blue 
  calcareous 
  and 
  slightly 
  carbonaceous 
  shales 
  with 
  Climacograptus 
  

  

  bicornis, 
  Diplogr. 
  rugosas, 
  &c. 
  

   (a) 
  Nodular 
  and 
  highly 
  calcareous 
  shales 
  crowded 
  with 
  fossils. 
  

   Ab 
  3 
  . 
  Compact 
  Limestones, 
  fossils 
  rare. 
  

   Ab 
  2 
  . 
  Impure 
  flaggy 
  and 
  nodular 
  limestones, 
  greatly 
  shattered 
  and 
  folded, 
  with 
  

  

  rare 
  Maclurea 
  Logani 
  and 
  abundant 
  corals. 
  

   Ab. 
  Sandy 
  and 
  flaggy 
  limestones 
  with 
  Orthis, 
  Leptcsna, 
  &c. 
  

   Kirkland 
  Conglomerate. 
  

  

  Aa. 
  Basal 
  brecciated 
  and 
  calcareous 
  conglomerate 
  and 
  grit. 
  

   x. 
  Igneous 
  and 
  altered 
  rocks 
  of 
  Craighead 
  Hill. 
  

   Car. 
  Lower 
  Carboniferous 
  sandstones 
  of 
  the 
  Girvan 
  valley. 
  

   //. 
  Faults. 
  

  

  The 
  floor 
  of 
  the 
  quarry 
  itself 
  and 
  the 
  little 
  cliff 
  supporting 
  the 
  

   roadway 
  to 
  the 
  south 
  is 
  composed 
  of 
  the 
  purer 
  and 
  more 
  compact 
  

   limestones 
  which 
  give 
  the 
  quarry 
  its 
  economic 
  value. 
  They 
  are 
  

   here 
  greatly 
  hardened 
  and 
  have 
  a 
  pale 
  greyish-white 
  tint 
  when 
  

   freshly 
  broken. 
  They 
  contain 
  a 
  larger 
  proportion 
  of 
  carbonate 
  

   of 
  lime 
  than 
  elsewhere, 
  and 
  seem 
  to 
  have 
  been 
  quarried 
  in 
  thick 
  

   and 
  heavy 
  masses. 
  A 
  few 
  of. 
  the 
  same 
  fossils 
  are 
  procurable 
  from 
  

   them 
  as 
  those 
  found 
  in 
  the 
  muddier 
  beds 
  below, 
  but 
  they 
  are 
  much 
  

   more 
  difficult 
  of 
  extraction. 
  

  

  The 
  terminal 
  beds 
  of 
  these 
  compact 
  limestones 
  are 
  seen 
  at 
  the 
  

   foot 
  of 
  a 
  boss 
  of 
  unexcavated 
  rock 
  which 
  at 
  present 
  divides 
  the 
  two 
  

   quarries 
  from 
  each 
  other. 
  This 
  boss 
  owes 
  its 
  existence 
  to 
  the 
  cir- 
  

   cumstance 
  that 
  the 
  strata 
  of 
  which 
  it 
  is 
  formed 
  contain 
  too 
  little 
  

   lime 
  to 
  be 
  available 
  for 
  burning 
  ; 
  and 
  they 
  have 
  been 
  allowed 
  to 
  

   remain, 
  while 
  the 
  surrounding 
  limestones 
  have 
  been 
  quarried 
  away. 
  

   The 
  strata 
  seen 
  in 
  this 
  boss 
  are, 
  however, 
  of 
  great 
  value 
  to 
  the 
  

   stratigraphist, 
  as 
  they 
  enable 
  him 
  to 
  complete 
  the 
  entire 
  section 
  of 
  

   the 
  calcareous 
  series 
  visible 
  at 
  this 
  locality. 
  

  

  In 
  the 
  western 
  cliff 
  of 
  this 
  mound 
  the 
  Compact 
  Limestones 
  are 
  

   seen 
  to 
  be 
  overlain 
  by 
  about 
  10 
  feet 
  of 
  grey 
  and 
  black 
  Graptolitic 
  

   shales, 
  identical 
  in 
  mineralogical 
  character 
  with 
  the 
  Didymograptus- 
  

   shales 
  ( 
  Ab 
  4 
  ) 
  of 
  the 
  Auchensoul 
  band. 
  They 
  contain 
  a 
  few 
  Graptolites 
  

   and 
  shells. 
  Of 
  the 
  former, 
  Mrs. 
  Gray 
  has 
  here 
  collected 
  Crypto 
  - 
  

   graptus 
  tricornis, 
  Carr., 
  sp., 
  and 
  Diplograptus 
  foliaceus, 
  Murch. 
  

  

  In 
  the 
  grass-grown, 
  flank 
  of 
  the 
  boss 
  on 
  its 
  south-west 
  aspect 
  

   these 
  Graptolitic 
  shales 
  pass 
  upwards 
  into 
  an 
  equal 
  thickness 
  of 
  hard 
  

  

  