﻿PROF. 
  C. 
  LAP 
  WORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  607 
  

  

  As 
  at 
  Whitehouse, 
  the 
  majority 
  of 
  the 
  Lower 
  Whitehouse 
  beds 
  

   consist 
  of 
  dark 
  grey 
  shales 
  striped 
  with 
  dark 
  lines 
  of 
  carbonaceous 
  

   matter, 
  and 
  containing 
  at 
  intervals 
  seams, 
  flags, 
  and 
  ribs 
  of 
  hard 
  

   calcareous 
  grit 
  or 
  " 
  cement-stone," 
  with 
  fragmentary 
  Brachiopoda. 
  

   Here, 
  however, 
  the 
  shales 
  are 
  much 
  looser 
  and 
  softer 
  in 
  texture, 
  and 
  

   are 
  altogether 
  much 
  more 
  fossiliferous 
  than 
  in 
  the 
  shore-section. 
  

   They 
  have, 
  indeed, 
  rather 
  the 
  character 
  of 
  the 
  soft 
  muddy 
  beds 
  of 
  

   this 
  group 
  a» 
  developed 
  in 
  the 
  lower 
  part 
  of 
  the 
  Byne-Hill 
  Burn 
  ; 
  

   and 
  the 
  fossils 
  they 
  contain 
  place 
  it 
  beyond 
  question 
  that 
  many 
  of 
  

   them 
  actually 
  appertain 
  to 
  that 
  special 
  zone. 
  The 
  majority 
  of 
  the 
  

   shales 
  weather 
  to 
  a 
  rusty-red 
  colour. 
  They 
  yield 
  the 
  following 
  

   Byne-Hill-Burn 
  Graptolithina 
  in 
  some 
  profusion, 
  and 
  in 
  a 
  most 
  

   perfect 
  state 
  of 
  preservation 
  : 
  — 
  

  

  Pleurograptus 
  linearis, 
  Carr. 
  

   Leptograptus 
  flaccidus, 
  Hall. 
  

   Climacograptus 
  tubuliferus, 
  Lapw. 
  

   Diplograptus 
  quadrimucronatus,.flrt#. 
  

  

  Diplograptus 
  foliaceus, 
  Murch. 
  

   — 
  — 
  truncatus, 
  Lapw. 
  

   Corynoides 
  calycularis, 
  Nick. 
  

  

  Upper 
  Whitehouse 
  Beds 
  (Bb 
  2). 
  — 
  In 
  the 
  place 
  where 
  we 
  should 
  

   expect 
  to 
  find 
  the 
  ribbed 
  mudstones 
  that 
  lead 
  up 
  into 
  the 
  purple 
  

   shales 
  of 
  the 
  upper 
  zones 
  of 
  the 
  Whitehouse 
  Beds 
  we 
  find 
  instead 
  a 
  

   thickness 
  of 
  nearly 
  100 
  feet 
  of 
  soft 
  dark 
  bluish-green 
  mudstones 
  

   devoid 
  of 
  ribs. 
  They 
  are 
  well 
  seen 
  in 
  the 
  bed 
  and 
  bounding 
  cliffs 
  of 
  

   the 
  burn, 
  forming 
  a 
  most 
  distinctive 
  band 
  in 
  the 
  rocky 
  succession. 
  

   They 
  break 
  up 
  under 
  the 
  hammer 
  first 
  into 
  beds 
  of 
  3 
  or 
  4 
  inches 
  

   thickness, 
  and 
  afterwards 
  into 
  irregular-sided 
  blocks, 
  with 
  a 
  clearly 
  

   marked 
  conchoidal 
  fracture. 
  As 
  a 
  rule, 
  no 
  fossils 
  whatever 
  seem 
  

   to 
  be 
  obtainable 
  from 
  these 
  beds, 
  though 
  they 
  look 
  very 
  promising 
  

   for 
  the 
  palaeontologist. 
  

  

  They 
  are 
  followed 
  immediately 
  by 
  a 
  very 
  meagre 
  representative 
  

   of 
  the 
  purple 
  and 
  green 
  mudstone 
  group, 
  of 
  which 
  only 
  a 
  few 
  feet 
  

   are 
  visible 
  in 
  the 
  bed 
  of 
  the 
  stream 
  ; 
  but 
  these 
  are 
  clearly 
  intercalated, 
  

   as 
  upon 
  the 
  shore-line, 
  between 
  the 
  grey 
  mudstones 
  last 
  referred 
  to 
  

   and 
  the 
  Barren 
  Flagstones, 
  which 
  next 
  form 
  the 
  cliffs 
  for 
  a 
  long 
  

   distance 
  down 
  the 
  stream. 
  These 
  variegated 
  mudstones, 
  though 
  

   wanting 
  in 
  their 
  proper 
  thickness, 
  probably 
  owing 
  to 
  the 
  presence 
  

   of 
  faults, 
  show 
  us, 
  nevertheless, 
  a 
  satisfactory 
  quantity 
  of 
  their 
  

   associated 
  calcareous 
  zones, 
  which 
  are 
  here 
  much 
  harder 
  and 
  more 
  

   flag-like 
  than 
  upon 
  the 
  shore. 
  

  

  Graptolites 
  are 
  difficult 
  to 
  procure 
  ; 
  a 
  few 
  fragments 
  of 
  Dictyo- 
  

   nema, 
  Ganocladium, 
  and 
  Climacograptus 
  are 
  all 
  that 
  I 
  have 
  been 
  

   able 
  to 
  identify 
  from 
  them. 
  But 
  Brachiopoda 
  are 
  abundant 
  in 
  the 
  

   thick-bedded 
  " 
  cement-stones 
  ; 
  " 
  examples 
  of 
  Leptama 
  tenuistriata, 
  

   Orthis 
  biforata, 
  Orthis 
  calligramma 
  and 
  their 
  usual 
  associates 
  are 
  

   by 
  no 
  means 
  rare. 
  

  

  (3) 
  Be. 
  Shalloch 
  or 
  Barren 
  Flagstones. 
  — 
  The 
  seam 
  of 
  purple 
  and 
  

   green 
  shales 
  of 
  the 
  Upper 
  Whitehousc-beds, 
  last 
  described, 
  has 
  a 
  

   thickness 
  of 
  about 
  30 
  feet. 
  It 
  is 
  succeeded 
  immediately 
  by 
  a 
  great 
  

   mass 
  of 
  Barren 
  Flagstones, 
  which 
  extend 
  down 
  the 
  course 
  of 
  the 
  

   stream 
  for 
  the 
  next 
  three 
  quarters 
  of 
  a 
  mile. 
  As 
  in 
  our 
  much 
  more 
  

  

  