﻿PKOF. 
  C. 
  LAPWOKTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  545 
  

  

  town 
  of 
  Girvan 
  ; 
  a 
  fifth 
  by 
  the 
  narrow 
  strip 
  of 
  Lower 
  Palaeozoic 
  

   rocks 
  forming 
  the 
  northward 
  slope 
  of 
  the 
  Hadyard 
  and 
  Garleffin 
  

   Hills 
  ; 
  and 
  a 
  sixth 
  by 
  the 
  lenticular 
  inlier 
  of 
  Craighead 
  and 
  Mulloch 
  

   Hill 
  near 
  Dailly. 
  

  

  The 
  whole 
  of 
  the 
  important 
  subarea 
  of 
  the 
  Benan 
  and 
  Milljoan 
  

   Hills, 
  together 
  with 
  much 
  of 
  the 
  adjoining 
  subareas, 
  is 
  floored 
  by 
  

   sheets 
  of 
  boulder-conglomerates 
  of 
  enormous 
  thickness 
  and 
  remark- 
  

   able 
  composition, 
  amid 
  which 
  lie 
  patches 
  and 
  lines 
  of 
  fossiliferous 
  

   limestones 
  scattered 
  confusedly 
  over 
  the 
  face 
  of 
  the 
  country. 
  The 
  

   Saugh-Hill 
  and 
  Knock-gerran 
  subareas 
  are 
  composed 
  of 
  repetitions 
  

   of 
  flagstones 
  and 
  grits 
  of 
  variable 
  composition, 
  occasionally 
  inter- 
  

   spersed 
  with 
  shell-bearing 
  pebble-beds 
  and 
  seams 
  of 
  purple 
  and 
  green 
  

   mudstone. 
  The 
  shelly 
  sandstones 
  and 
  Trinucleus-shalea, 
  for 
  which 
  

   the 
  Girvan 
  district 
  has 
  long 
  been 
  famous, 
  occur 
  only 
  in 
  the 
  Craighead 
  

   and 
  Mulloch-Hill 
  area 
  which 
  lies 
  to 
  the 
  north 
  of 
  the 
  Girvan 
  valley. 
  

   The 
  barren 
  strata 
  exhibited 
  in 
  the 
  fringing 
  subarea 
  of 
  Dailly 
  and 
  

   Straiton 
  to 
  the 
  south 
  of 
  that 
  valley 
  remind 
  us 
  of 
  the 
  greywackes 
  

   and 
  flagstones 
  of 
  the 
  Southern 
  Uplands. 
  

  

  The 
  strike 
  of 
  the 
  Lower 
  Palaeozoic 
  rocks 
  of 
  the 
  Girvan 
  district 
  is 
  

   uniformly 
  from 
  N.E. 
  to 
  S.W. 
  The 
  dip 
  of 
  the 
  beds 
  varies. 
  In 
  the 
  

   northern 
  parts 
  of 
  the 
  main 
  plateau 
  they 
  dip 
  steeply 
  to 
  the 
  south- 
  

   east, 
  while 
  to 
  the 
  south 
  they 
  have 
  as 
  distinctly 
  a 
  north-westerly 
  

   inclination. 
  Hence 
  the 
  majority 
  of 
  geologists 
  have 
  hitherto 
  regarded 
  

   the 
  rocks 
  of 
  this 
  plateau 
  as 
  forming 
  a 
  regular 
  synclinal 
  trough, 
  whos^e 
  

   oldest 
  strata 
  lay 
  along 
  the 
  outer 
  edges 
  of 
  the 
  plateau 
  and 
  the 
  newest 
  

   in 
  its 
  centre. 
  

  

  Two 
  gigantic 
  faults 
  have 
  long 
  been 
  recognized 
  as 
  affecting 
  the 
  

   stratified 
  rocks 
  of 
  this 
  district. 
  These 
  occur 
  on 
  the 
  opposite 
  slopes 
  of 
  

   the 
  valley 
  of 
  the 
  Girvan, 
  running 
  approximately 
  parallel 
  to 
  the 
  

   general 
  course 
  of 
  that 
  stream, 
  and 
  throwing 
  down 
  between 
  them 
  a 
  

   broad 
  band 
  of 
  Carboniferous 
  strata, 
  from 
  two 
  to 
  four 
  miles 
  in 
  width. 
  

   The 
  northern, 
  or 
  Craighead 
  fault, 
  has 
  been 
  proved 
  for 
  a 
  distance 
  of 
  

   about 
  21 
  miles 
  ; 
  while 
  the 
  southern, 
  or 
  Bargany 
  fault, 
  is 
  in 
  all 
  

   probability 
  of 
  equal 
  longitudinal 
  extent. 
  The 
  general 
  direction 
  of 
  

   these 
  faults 
  is 
  from 
  N.E. 
  to 
  S.W. 
  ; 
  in 
  other 
  words, 
  their 
  courses 
  

   coincide 
  with 
  the 
  general 
  strike 
  of 
  the 
  Lower 
  Palaeozoic 
  rocks 
  of 
  

   the 
  region. 
  They 
  are, 
  in 
  reality, 
  strike-faults, 
  whose 
  existence 
  

   would 
  long 
  have 
  remained 
  unsuspected 
  were 
  it 
  not 
  for 
  the 
  fact 
  

   that, 
  with 
  respect 
  to 
  the 
  overlying 
  Carboniferous 
  strata, 
  they 
  are 
  

   more 
  or 
  less 
  dip-faults, 
  abruptly 
  truncating 
  the 
  gently 
  inclined 
  

   Carboniferous 
  beds, 
  and 
  flinging 
  them 
  down 
  along 
  two 
  compara- 
  

   tively 
  straight 
  lines 
  among 
  the 
  perpendicular 
  or 
  highly 
  convoluted 
  

   Lower 
  Palaeozoic 
  rocks 
  below. 
  

  

  A 
  third 
  fault, 
  running 
  along 
  the 
  southern 
  slope 
  of 
  the 
  valley 
  of 
  the 
  

   Stinchar 
  and 
  having 
  the 
  same 
  general 
  N.E. 
  to 
  S.W. 
  trend 
  as 
  the 
  fore- 
  

   going, 
  was 
  detected 
  by 
  Prof. 
  A. 
  Geikie 
  during 
  his 
  detailed 
  mapping 
  

   of 
  the 
  district. 
  By 
  the 
  officers 
  of 
  the 
  Geological 
  Survey 
  the 
  fault 
  

   was 
  originally 
  looked 
  upon 
  as 
  forming 
  the 
  southern 
  limit 
  of 
  the 
  

   Girvan 
  district 
  proper. 
  The 
  barren 
  and 
  monotonous 
  strata 
  lying 
  to 
  

   the 
  south 
  of 
  this 
  fault 
  were 
  classed 
  as 
  being 
  of 
  Llandeilo 
  age, 
  while 
  

  

  