﻿PEOE. 
  C. 
  LAPWOETH 
  OX 
  THE 
  GTEVAX 
  SUCCESSION. 
  581 
  

  

  excavated 
  in 
  the 
  south-west 
  flank 
  of 
  the 
  prominent 
  ridge 
  of 
  Craighead 
  

   and 
  Quarrel 
  Hill, 
  in 
  the 
  immediate 
  neighbourhood 
  of 
  the 
  Glasgow 
  

   and 
  South-western 
  Railway, 
  about 
  a 
  mile 
  to 
  the 
  east 
  of 
  the 
  railway- 
  

   station 
  of 
  Killochan. 
  The 
  gigantic 
  fault 
  which 
  here 
  forms 
  the 
  

   northern 
  limit 
  of 
  the 
  Carboniferous 
  basin 
  of 
  the 
  Girvan 
  valley 
  runs 
  

   at 
  this 
  point 
  parallel 
  to 
  the 
  railway, 
  immediately 
  in 
  front 
  of 
  the 
  

   quarries 
  themselves. 
  Several 
  loop-faults 
  or 
  inosculating 
  branches 
  

   of 
  this 
  grand 
  dislocation 
  are 
  given 
  off 
  along 
  its 
  course 
  to 
  the 
  north- 
  

   westward 
  ; 
  and 
  caught 
  up 
  between 
  these, 
  and 
  abruptly 
  collocated 
  with 
  

   strata 
  of 
  comparatively 
  recent 
  geological 
  age, 
  we 
  find 
  long 
  lenticular 
  

   masses 
  of 
  the 
  conglomeratic 
  and 
  calcareous 
  division 
  of 
  the 
  Girvan 
  

   succession 
  we 
  have 
  been 
  studying 
  to 
  the 
  southward. 
  The 
  most 
  im- 
  

   portant 
  of 
  these 
  loop-faults 
  surrounds 
  the 
  mound-like 
  hill 
  of 
  Craig- 
  

   head, 
  enclosing 
  a 
  lenticular 
  mass 
  of 
  rock 
  of 
  peculiar 
  character, 
  a 
  mile 
  

   in 
  length 
  and 
  half 
  a 
  mile 
  in 
  breadth. 
  The 
  main 
  mass 
  of 
  the 
  lenticle, 
  

   which 
  forms 
  the 
  hill 
  itself, 
  is 
  clearly 
  identical 
  with 
  the 
  enigmatical 
  

   rocks 
  of 
  Ballantrae, 
  and, 
  like 
  them, 
  is 
  formed 
  of 
  a 
  congeries 
  of 
  rocks 
  

   partly 
  aqueous 
  and 
  partly 
  igneous, 
  the 
  latter, 
  again, 
  being 
  partly 
  

   bedded 
  and 
  contemporaneous, 
  partly 
  intrusive 
  and 
  subsequent. 
  At 
  

   the 
  eastern 
  end 
  of 
  the 
  lenticle, 
  however, 
  these 
  rocks 
  are 
  surrounded 
  

   by 
  a 
  mass 
  of 
  limestone 
  and 
  calcareous 
  strata, 
  of 
  a 
  semicircular 
  form, 
  

   limited 
  at 
  both 
  ends 
  by 
  the 
  bounding 
  faults, 
  and 
  dipping 
  generally 
  

   from 
  off 
  the 
  igneous 
  and 
  hardened 
  rocks. 
  

  

  It 
  is 
  in 
  this 
  semicircular 
  mass 
  of 
  limestone 
  that 
  the 
  Craighead 
  

   quarries 
  have 
  been 
  excavated. 
  They 
  are 
  two 
  in 
  number 
  — 
  an 
  older 
  

   quarry 
  lying 
  on 
  the 
  southern 
  curve 
  of 
  the 
  semicircle, 
  and 
  a 
  newer 
  

   quarry 
  running 
  along 
  its 
  eastern 
  edge. 
  The 
  former 
  has 
  been 
  long 
  

   exhausted 
  of 
  its 
  superficial 
  and 
  more 
  easily 
  excavated 
  limestones. 
  

   The 
  latter 
  is 
  in 
  constant 
  working 
  to 
  supply 
  the 
  demands 
  of 
  the 
  agricul- 
  

   turists 
  of 
  the 
  neighbourhood, 
  the 
  lime 
  being 
  burnt 
  in 
  kilns 
  upon 
  

   the 
  spot, 
  and 
  delivered 
  by 
  special 
  tramway 
  at 
  the 
  railway- 
  station 
  

   of 
  Killochan. 
  

  

  The 
  general 
  arrangement 
  of 
  the 
  calcareous 
  rocks 
  of 
  this 
  locality 
  

   will 
  be 
  apparent 
  on 
  a 
  study 
  of 
  the 
  following 
  section 
  (fig. 
  13). 
  

  

  The 
  two 
  sets 
  of 
  calcareous 
  strata 
  excavated 
  in 
  the 
  quarries 
  form, 
  

   with 
  respect 
  to 
  each 
  other, 
  a 
  rude 
  synclinal, 
  which 
  has 
  been 
  broken 
  

   along 
  its 
  central 
  line. 
  Their 
  physical 
  arrangement 
  is 
  best 
  displayed 
  

   in 
  a 
  section 
  drawn 
  through 
  the 
  south 
  quarry 
  parallel 
  to 
  the 
  great 
  

   fault. 
  

  

  At 
  the 
  south-western 
  end 
  of 
  the 
  quarry 
  calcareous 
  and 
  ashy 
  con- 
  

   glomerates, 
  representative 
  of 
  the 
  basal 
  conglomerates 
  of 
  Kirkland 
  

   (Aa), 
  are 
  seen 
  in 
  vertical 
  and 
  even 
  partially 
  inverted 
  position 
  in 
  

   contact 
  with 
  the 
  igneous 
  rocks 
  of 
  Craighead 
  Hill. 
  They 
  pass 
  below 
  

   a 
  thick 
  group 
  of 
  nodular 
  beds 
  (Ab 
  1 
  and 
  Ab), 
  which, 
  arranged 
  in 
  a 
  

   basin-like 
  form, 
  run 
  in 
  perpendicular 
  cliffs 
  round 
  the 
  western 
  and 
  

   northern 
  faces 
  of 
  the 
  quarry. 
  These 
  are 
  actually 
  concretionary 
  

   limestones, 
  rendered 
  very 
  impure 
  by 
  the 
  presence 
  of 
  much 
  soft 
  green 
  

   and 
  grey 
  mud. 
  They 
  contain 
  an 
  occasional 
  Maclurea, 
  and 
  are 
  

   crowded 
  with 
  an 
  abundance 
  of 
  corals, 
  the 
  beautiful 
  tracery 
  of 
  which 
  

   may 
  be 
  made 
  out 
  by 
  the 
  lens 
  in 
  all 
  the 
  white 
  seams 
  and 
  bands 
  that 
  

   traverse 
  the 
  face 
  of 
  every 
  new-made 
  fracture 
  of 
  the 
  beds. 
  

  

  