﻿PROF. 
  C. 
  LAPWORTH 
  OX 
  THE 
  GIRVAN 
  STTGCESSION. 
  609 
  

  

  It 
  will 
  next 
  be 
  shown 
  that 
  a 
  corresponding 
  arrangement 
  obtains 
  

   universally 
  among 
  the 
  remaining 
  exposures 
  in 
  the 
  Girvan 
  district. 
  

  

  (d) 
  Additional 
  Exposures 
  of 
  the 
  Graptolitie 
  Flagstones 
  south 
  of 
  the 
  

   Girvan 
  Valley. 
  

  

  1. 
  Area 
  of 
  Pinmore 
  and 
  Letterpin. 
  — 
  The 
  long 
  strip 
  of 
  Ardmillan 
  

   shales 
  which 
  stretches 
  from 
  Daldowie 
  south-eastward 
  to 
  the 
  valley 
  

   of 
  the 
  Lendal, 
  affords 
  us 
  by 
  far 
  the 
  most 
  satisfactory 
  exposures 
  of 
  

   the 
  Ardwell 
  Shales 
  considered 
  in 
  their 
  fossiliferous 
  character. 
  The 
  

   line 
  of 
  railway 
  running 
  from 
  Girvan 
  to 
  Stranraer 
  traverses 
  the 
  

   district 
  almost 
  at 
  right 
  angles 
  to 
  the 
  strike 
  of 
  the 
  beds 
  ; 
  and 
  its 
  

   cuttings 
  afford 
  a 
  magnificent 
  and 
  practically 
  unbroken 
  section 
  from 
  

   the 
  bottom 
  to 
  the 
  top 
  of 
  the 
  series 
  as 
  there 
  exhibited. 
  The 
  lowest 
  

   strata 
  exposed 
  are 
  certain 
  green 
  concretionary 
  mudstones 
  which 
  are 
  

   seen 
  in 
  the 
  roadway 
  underneath 
  the 
  great 
  viaduct 
  of 
  Kinclaer. 
  

   These 
  probably 
  belong 
  to 
  the 
  transitional 
  Balclatchie 
  group, 
  the 
  

   main 
  mass 
  of 
  whose 
  beds 
  are 
  cut 
  out 
  by 
  a 
  small 
  fault 
  ranging 
  along 
  

   the 
  strike 
  of 
  the 
  rocks 
  between 
  that 
  exposure 
  and 
  the 
  great 
  masses 
  

   of 
  Benan 
  Conglomerate 
  visible 
  on 
  the 
  hills 
  to 
  the 
  southward 
  and 
  in 
  

   the 
  stream-bed 
  of 
  the 
  River 
  Assel 
  a 
  few 
  yards 
  below. 
  

  

  Above 
  these 
  green 
  mudstones 
  follows 
  a 
  great 
  thickness 
  of 
  very 
  

   dark 
  greyish-blue 
  shales, 
  beautifully 
  shown 
  in 
  the 
  railway- 
  cutting, 
  

   dipping 
  steadily 
  to 
  the 
  north-eastward 
  at 
  an 
  angle 
  of 
  about 
  30°. 
  

   They 
  are 
  fully 
  as 
  indurated 
  as 
  their 
  counterparts 
  in 
  the 
  lower 
  por- 
  

   tion 
  of 
  our 
  typical 
  section 
  of 
  Ardwell 
  shore 
  ; 
  but, 
  in 
  place 
  of 
  being 
  

   practically 
  barren, 
  many 
  of 
  their 
  laminae 
  are 
  covered 
  with 
  easily 
  

   identified 
  examples 
  of 
  : 
  — 
  

  

  Dicranograptus 
  Mcholsoni, 
  HopJc. 
  Clirnacograptus 
  caudatus, 
  Lapiv. 
  

  

  Dicellograptus 
  Forckhammeri, 
  Gerv. 
  bicornis, 
  His. 
  

  

  Diplograptus 
  foliaceus, 
  Murch. 
  J 
  Leptograptus 
  flaccidus, 
  var. 
  Hall. 
  

  

  rugosus, 
  Emmons. 
  j 
  Corynoides 
  calycularis, 
  Nick. 
  

  

  Cryptograptus 
  tricornis, 
  Carr. 
  &c. 
  

  

  Numerous 
  scattered 
  exposures 
  in 
  quarries 
  and 
  in 
  the 
  railway- 
  

   cuttings 
  enable 
  us 
  to 
  complete 
  the 
  section 
  as 
  far 
  as 
  Letterpin 
  fault. 
  

   The 
  beds 
  remain 
  essentially 
  the 
  same 
  throughout. 
  As 
  we 
  near 
  the 
  

   railway-station 
  seams 
  of 
  cement-stone, 
  grits 
  with 
  angular 
  quartz- 
  

   pebbles, 
  and 
  patches 
  of 
  coarse 
  brown 
  and 
  more 
  or 
  less 
  calcareous 
  

   flagstones 
  make 
  their 
  appearance 
  at 
  irregular 
  intervals. 
  Some 
  of 
  

   these 
  probably 
  belong 
  to 
  the 
  underlying 
  Balclatchie 
  Beds. 
  They 
  

   contain 
  many 
  specimens 
  of 
  Brachiopoda, 
  usually 
  in 
  a 
  fragmentary 
  

   but 
  easily 
  recognizable 
  condition. 
  

  

  These 
  Balclatchie 
  and 
  Ardmillan 
  strata, 
  a 
  little 
  further 
  to 
  the 
  

   west, 
  bear 
  evidence 
  of 
  being 
  arranged 
  more 
  or 
  less 
  in 
  a 
  synclinal 
  

   form. 
  The 
  coarse 
  yellow 
  gritstones 
  with 
  fossils, 
  seen 
  in 
  the 
  nu- 
  

   merous 
  quarries 
  around 
  Mickle 
  Letterpin 
  and 
  Chapelcroft, 
  are 
  

   probably 
  identical 
  with 
  the 
  Balclatchie 
  zones 
  of 
  the 
  railway-cutting, 
  

   and 
  are 
  well 
  exposed 
  in 
  many 
  quarries 
  and 
  small 
  natural 
  sections 
  

   over 
  the 
  fields 
  in 
  the 
  neighbourhood 
  of 
  the 
  Letterpin 
  fault. 
  

  

  