﻿616 
  PROP. 
  C. 
  LAPWORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  The 
  lowest 
  beds 
  of 
  the 
  Flagstone 
  series 
  visible 
  at 
  this 
  locality 
  are 
  

   seen 
  at 
  the 
  head 
  of 
  the 
  little 
  burn, 
  circling 
  round 
  the 
  declining 
  

   axis 
  of 
  the 
  main 
  anticlinal 
  arch, 
  and 
  gradually 
  acquiring 
  a 
  steep 
  

   southward 
  inclination 
  as 
  we 
  descend 
  the 
  course 
  of 
  the 
  stream. 
  The 
  

   oldest 
  beds 
  are 
  greyish-green 
  flagstones, 
  from 
  two 
  to 
  four 
  inches 
  

   in 
  thickness, 
  separated 
  by 
  the 
  usual 
  pale 
  bluish-green 
  seams 
  of 
  

   shaly 
  sandstone, 
  characteristic 
  of 
  the 
  higher 
  parts 
  of 
  the 
  " 
  Barren 
  

   Flagstones 
  " 
  as 
  seen 
  near 
  the 
  Saugh-Hill 
  fault 
  in 
  the 
  gorge 
  of 
  Pen- 
  

   whapple. 
  They 
  contain 
  their 
  peculiar 
  fossil, 
  Nematolites 
  Grayii, 
  

   Lapw., 
  in 
  some 
  abundance, 
  together 
  with 
  a 
  few 
  scattered 
  examples 
  of 
  

   the 
  equally 
  characteristic 
  Graptolite 
  Diplograptus 
  truncatus, 
  Lapw. 
  

  

  Lower 
  down 
  the 
  stream 
  the 
  flagstones 
  and 
  shales 
  differentiate 
  

   themselves 
  in 
  wider 
  bands, 
  and 
  the 
  strata 
  put 
  on 
  an 
  appearance 
  

   identical 
  with 
  that 
  of 
  the 
  most 
  typical 
  Barren 
  Flagstones 
  of 
  Pen- 
  

   whapple, 
  showing 
  the 
  same 
  regular 
  alternation 
  of 
  a 
  foot 
  of 
  hard 
  

   grey 
  grit 
  with 
  two 
  or 
  four 
  feet 
  of 
  greenish 
  flaky 
  shales. 
  Below 
  the 
  

   little 
  wood 
  the 
  beds 
  become 
  steeper, 
  and, 
  as 
  will 
  be 
  seen 
  from 
  the 
  

   map 
  (PI. 
  XXV. 
  4) 
  and 
  sections, 
  begin 
  to 
  be 
  much 
  broken 
  up 
  by 
  

   faults. 
  Their 
  highest 
  beds 
  as 
  seen 
  here 
  are 
  pale 
  flagstones, 
  with 
  a 
  

   light-blue 
  interior, 
  associated 
  with 
  similarly 
  tinted 
  mudstones, 
  both 
  

   weathering 
  to 
  the 
  dull 
  orange-buff 
  colour 
  affected 
  by 
  the 
  beds 
  of 
  

   this 
  formation 
  whereevcr 
  they 
  have 
  been 
  long 
  exposed 
  to 
  the 
  action 
  

   of 
  the 
  atmosphere. 
  

  

  A 
  confirmatory 
  section 
  is 
  visible 
  in 
  Farden 
  Burn, 
  about 
  three 
  

   fourths 
  of 
  a 
  mile 
  to 
  the 
  south-westward 
  of 
  Quarrel 
  Hill. 
  The 
  

   oldest 
  beds, 
  ranging 
  along 
  the 
  anticlinal 
  line, 
  occur 
  in 
  the 
  banks 
  of 
  

   the 
  stream 
  at 
  the 
  back 
  of 
  the 
  farmsteading 
  of 
  Farden, 
  dipping 
  in 
  

   opposite 
  directions 
  at 
  a 
  small 
  angle. 
  As 
  we 
  descend 
  the 
  stream 
  to 
  

   the 
  south 
  the 
  angle 
  of 
  inclination 
  rapidly 
  increases 
  ; 
  and 
  between 
  the 
  

   steading 
  and 
  the 
  Craighead 
  fault 
  we 
  pass 
  over 
  a 
  fairly 
  continuous 
  

   section 
  of 
  these 
  beds, 
  the 
  majority 
  of 
  which 
  are 
  identical 
  with 
  the 
  

   pale 
  and 
  buff-coloured 
  flags 
  and 
  shales 
  that 
  terminate 
  the 
  exposure 
  

   in 
  Q,uarrel-Hill 
  Burn, 
  while 
  they 
  are 
  similarly 
  destitute 
  of 
  organic 
  

   remains 
  of 
  any 
  kind. 
  

  

  These 
  Barren 
  Flagstones 
  are 
  seen 
  upon 
  the 
  opposite 
  side 
  of 
  the 
  

   anticlinal 
  line 
  in 
  two 
  localities 
  only. 
  One 
  of 
  these 
  occurs 
  in 
  an 
  old 
  

   quarry 
  a 
  quarter 
  of 
  a 
  mile 
  to 
  the 
  west 
  of 
  Blair 
  Farm, 
  the 
  other 
  on 
  

   the 
  road-side 
  at 
  the 
  farm-house 
  itself. 
  In 
  both 
  localities 
  we 
  find 
  the 
  

   barren 
  buff- 
  weathering 
  shale 
  and 
  flagstones 
  of 
  the 
  highest 
  zone 
  of 
  

   the 
  series, 
  as 
  usual, 
  perfectly 
  destitute 
  of 
  fossils. 
  

  

  The 
  numerous 
  faults 
  and 
  folds 
  of 
  the 
  district 
  do 
  not 
  allow 
  an 
  

   exact 
  calculation 
  of 
  the 
  vertical 
  thickness 
  of 
  the 
  portion 
  of 
  the 
  Shal- 
  

   loch 
  or 
  Barren-flagstone 
  group 
  as 
  here 
  exposed. 
  It 
  may 
  be 
  roughly 
  

   estimated 
  at 
  about 
  300 
  feet. 
  The 
  buff-tinted 
  terminal 
  band 
  of 
  

   flagstones 
  and 
  shales 
  cannot 
  be 
  less 
  than 
  100 
  feet 
  in 
  total 
  thick- 
  

   ness. 
  This 
  is 
  apparently 
  wanting 
  in 
  the 
  Penwhapple 
  exposure 
  of 
  

   these 
  beds, 
  and 
  its 
  thickness 
  falls 
  to 
  be 
  added 
  to 
  our 
  estimate 
  of 
  

   the 
  vertical 
  extent 
  of 
  the 
  Barren 
  Flagstones 
  of 
  that 
  area. 
  This 
  

   would 
  give 
  a 
  collective 
  thickness 
  of 
  about 
  800 
  feet 
  to 
  the 
  entire 
  for- 
  

   mation 
  of 
  the 
  Barren 
  Flagstones 
  as 
  seen 
  in 
  the 
  Girvan 
  region. 
  

  

  