﻿PROF. 
  C. 
  LAPWORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  599 
  

  

  come 
  upon 
  the 
  band 
  of 
  purple 
  and 
  green 
  mudstone 
  in 
  Woodland 
  Bay. 
  

   Here 
  only 
  a 
  few 
  feet 
  of 
  the 
  ribbed 
  shales 
  are 
  discernible, 
  projecting 
  

   from 
  the 
  sand 
  of 
  the 
  beach 
  ; 
  but 
  there 
  seems 
  to 
  be 
  a 
  fairly 
  unbroken 
  

   section 
  from 
  these 
  ribbed 
  beds 
  into 
  the 
  basal 
  beds 
  of 
  the 
  succeeding 
  

   Barren-flagstone 
  group, 
  through 
  the 
  purple 
  mudstoncs 
  and 
  Dionide- 
  

   seams, 
  though 
  only 
  a 
  few 
  fragmentary 
  Graptolites 
  are 
  obtainable 
  

   among 
  the 
  shattered 
  and 
  sodden 
  strata. 
  

  

  For 
  the 
  next 
  quarter 
  of 
  a 
  mile 
  the 
  Whitehouse 
  Beds 
  are 
  generally 
  

   hidden 
  from 
  sight 
  below 
  the 
  sandy 
  beach 
  of 
  Woodland 
  Bay 
  ; 
  but 
  

   where 
  they 
  next 
  put 
  in 
  an 
  appearance, 
  viz. 
  in 
  Myoch 
  Bay, 
  upon 
  the 
  

   shore-line 
  near 
  Shalloch 
  Mill, 
  we 
  have 
  by 
  far 
  the 
  most 
  complete 
  

   and 
  satisfactory 
  exposure 
  of 
  their 
  upper 
  zones 
  in 
  the 
  Girvan 
  district. 
  

  

  The 
  geographical 
  relations 
  of 
  these 
  beds 
  upon 
  the 
  ground 
  are 
  given 
  

   in 
  the 
  following 
  sketch 
  plan 
  (fig. 
  17) 
  ; 
  and 
  the 
  interrelationship 
  of 
  the 
  

   various 
  component 
  zones 
  will 
  be 
  evident 
  upon 
  a 
  study 
  of 
  the 
  accom- 
  

   panying 
  section. 
  

  

  Myoch 
  Bay. 
  — 
  The 
  deepest 
  strata 
  shown 
  in 
  the 
  continuous 
  section 
  

   laid 
  open 
  from 
  S. 
  to 
  N. 
  across 
  the 
  exposure 
  in 
  the 
  floor 
  of 
  Myoch 
  

   Bay, 
  are 
  the 
  coarse, 
  thick-bedded 
  and 
  gritty 
  sandstones 
  recognized 
  

   by 
  us 
  in 
  the 
  faulted 
  patch 
  at 
  Port 
  Cardloch. 
  Next 
  succeed 
  the 
  green 
  

   shales, 
  with 
  ribs 
  of 
  harder 
  and 
  gritty 
  flags. 
  Of 
  these 
  at 
  least 
  about 
  

   forty 
  feet 
  are 
  exposed, 
  forming 
  some 
  jagged 
  reefs 
  to 
  the 
  right 
  of 
  the 
  

   little 
  grassy 
  head] 
  and 
  south 
  of 
  the 
  bay. 
  

  

  Above 
  follows 
  the 
  first 
  band 
  of 
  the 
  Upper 
  Whitehouse 
  group, 
  

   consisting 
  of 
  about 
  15 
  feet 
  of 
  soft 
  green 
  mudstones 
  and 
  shales, 
  

   with 
  lines 
  of 
  purple 
  mudstone. 
  These 
  are 
  easily 
  followed 
  for 
  some 
  

   distance 
  round 
  the 
  corner 
  of 
  the 
  little 
  headland 
  to 
  the 
  south, 
  much 
  

   interfered 
  with, 
  however, 
  by 
  numerous 
  longitudinal 
  and 
  transverse 
  

   faults. 
  

  

  The 
  central 
  parts 
  of 
  the 
  bay 
  are 
  wholly 
  occupied 
  by 
  the 
  Upper 
  

   Whitehouse 
  Beds. 
  To 
  the 
  S.E. 
  lies 
  the 
  zone 
  of 
  purple 
  mudstones. 
  

   These 
  are 
  bent 
  into 
  innumerable 
  folds 
  and 
  wrinkles, 
  and 
  are 
  dug 
  out 
  

   into 
  the 
  usual 
  broad 
  hollow. 
  It 
  is 
  difficult 
  to 
  estimate 
  their 
  thick- 
  

   ness 
  ; 
  but 
  this 
  cannot 
  be 
  more 
  than 
  about 
  30 
  feet. 
  They 
  are 
  followed 
  

   to 
  the 
  north 
  by 
  the 
  second 
  transitional 
  zone 
  of 
  green 
  mudstones 
  

   with 
  purple 
  seams, 
  which 
  passes 
  upwards 
  into 
  the 
  fossiliferous 
  

   division 
  that 
  terminates 
  the 
  banded 
  series. 
  These 
  Upper 
  transi- 
  

   tional 
  beds 
  have 
  an 
  estimated 
  thickness 
  of 
  about 
  20 
  feet. 
  

  

  The 
  final 
  or 
  fossiliferous 
  subgroup 
  is 
  greatly 
  contorted 
  and 
  broken 
  ; 
  

   but 
  when 
  carefully 
  mapped 
  in 
  detail 
  the 
  following 
  succession 
  is 
  

   easily 
  made 
  out 
  : 
  — 
  

  

  (1) 
  Dicellog 
  raptus 
  complanatus 
  zone. 
  Black 
  shales, 
  highly 
  car- 
  

   bonaceous, 
  with 
  a 
  few 
  seams 
  of 
  grey 
  mudstone 
  and 
  calcareous 
  grit, 
  

   crowded 
  with 
  Graptolites 
  (5 
  feet). 
  

  

  Diplograptus 
  socialis, 
  Lapw., 
  is 
  the 
  commonest 
  form, 
  and 
  occurs 
  

   in 
  hosts. 
  Less 
  frequent 
  are 
  the 
  forms 
  named 
  in 
  the 
  following 
  

   list 
  :— 
  

  

  Climacograptus 
  tubuliferus, 
  Lapw. 
  

   Dicellograptus 
  complanatus, 
  Lapw. 
  

   Morrisi, 
  Hopk. 
  

  

  Theca 
  triangularis, 
  Portlock. 
  

   Lingula. 
  

  

  