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  PROF. 
  C. 
  LAPWOKTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  593 
  

  

  forced 
  to 
  regard 
  trie 
  first 
  major 
  formation 
  or 
  division 
  of 
  the 
  Girvan 
  

   Succession 
  as 
  being 
  terminated 
  above 
  by 
  the 
  final 
  zone 
  of 
  the 
  Bal- 
  

   clatchie 
  Beds 
  last 
  described, 
  the 
  overlying 
  Graptoliferous 
  flag- 
  

   stones 
  and 
  shales 
  of 
  Ardwell 
  forming 
  the 
  first 
  member 
  of 
  a 
  second 
  

   and 
  succeeding 
  division. 
  

  

  The 
  facts 
  adduced 
  in 
  the 
  preceding 
  pages 
  render 
  it 
  absolutely 
  

   certain 
  that 
  the 
  great 
  Benan 
  Conglomerate 
  (Ac), 
  which 
  we 
  originally 
  

   selected 
  as 
  our 
  general 
  horizon 
  of 
  reference, 
  is 
  everywhere 
  underlain 
  

   by 
  the 
  Stinchar 
  Limestone 
  (Ab), 
  and 
  its 
  associated 
  basal 
  conglo- 
  

   merate 
  and 
  sandstone 
  of 
  Kirkland 
  and 
  Craighead, 
  and 
  everywhere 
  

   overlain 
  by 
  the 
  transitional 
  zone 
  of 
  Balclatchie 
  (Ad). 
  From 
  the 
  

   base 
  of 
  the 
  Kirkland 
  Conglomerate 
  to 
  the 
  summit 
  of 
  the 
  Balclatchie 
  

   Beds, 
  the 
  sequence 
  is 
  demonstrably 
  continuous 
  ; 
  while 
  the 
  various 
  

   fossiliferous 
  subformations 
  are 
  united 
  by 
  a 
  general 
  community 
  of 
  

   organic 
  remains. 
  We 
  therefore 
  regard 
  the 
  strata 
  within 
  these 
  

   limits 
  as 
  collectively 
  constituting 
  the 
  first 
  recognizable 
  major 
  di- 
  

   vision 
  or 
  formation 
  in 
  the 
  Girvan 
  Succession. 
  

  

  To 
  this 
  primary 
  division 
  we 
  assign 
  the 
  title 
  of 
  the 
  Barr 
  Series, 
  

   after 
  the 
  name 
  of 
  the 
  village 
  where 
  its 
  strata 
  are 
  most 
  effectively 
  

   displayed 
  to 
  the 
  investigator. 
  The 
  entire 
  division 
  may 
  be 
  broadly 
  

   defined 
  as 
  a 
  series 
  of 
  conglomerates 
  and 
  boulder-beds, 
  relieved 
  by 
  

   zones 
  of 
  limestone, 
  sandstones, 
  and 
  fossiliferous 
  shales. 
  Its 
  compo- 
  

   nent 
  subformations, 
  as 
  we 
  have 
  seen, 
  vary 
  greatly 
  in 
  thickness, 
  

   even 
  within 
  the 
  limits 
  of 
  the 
  Girvan 
  region 
  ; 
  but 
  they 
  everywhere 
  

   retain 
  the 
  same 
  stratigraphical 
  interrelations, 
  lithological 
  features, 
  

   and 
  characteristic 
  organic 
  remains. 
  

  

  The 
  ascending 
  order 
  among 
  the 
  several 
  members 
  of 
  the 
  Barr 
  

   Series 
  is 
  given 
  in 
  the 
  following 
  Table 
  : 
  — 
  

  

  A. 
  Barr 
  series. 
  (700 
  to 
  1000 
  feet.) 
  

  

  Aa. 
  Kirkland 
  or 
  Purple 
  Conglomei'ate 
  and 
  Sandstone 
  30-200 
  feet. 
  

  

  Ab. 
  Stinchar 
  or 
  Craighead 
  Limestone 
  Group 
  100-150 
  ,, 
  

  

  Ab 
  1 
  . 
  Orthis-con 
  finis 
  flagstones. 
  

  

  Ab 
  2 
  . 
  Maclurea-beds. 
  

  

  Ab 
  3 
  . 
  Compact 
  Limestones. 
  

  

  Ab 
  4 
  . 
  Didymogra/ptus-sh 
  ales. 
  

  

  Ac. 
  Ben 
  an 
  or 
  Green 
  Conglomerate 
  500-600 
  ,, 
  

  

  Ad. 
  Balclatchie 
  Beds 
  80-100 
  „ 
  

  

  Ad 
  1 
  . 
  Balclatchie 
  Mudstones. 
  

  

  Ad 
  2 
  . 
  Balclatchie 
  Grits 
  and 
  Conglomerate. 
  

  

  (h) 
  Description 
  of 
  the 
  Typical 
  Section 
  of 
  the 
  Graptolitic 
  -flagstone 
  

   Series 
  of 
  Archnillan 
  Shore. 
  

  

  As 
  we 
  have 
  already 
  pointed 
  out, 
  the 
  great 
  Barr 
  or 
  Stinchar 
  series, 
  

   which 
  is 
  terminated 
  above 
  by 
  the 
  fossiliferous 
  zone 
  of 
  the 
  Balclatchie 
  

   beds 
  last 
  described, 
  is 
  bounded 
  everywhere 
  on 
  its 
  northern 
  or 
  upper 
  

   margin 
  by 
  a 
  group 
  of 
  flagstones 
  which 
  occupy 
  collectively 
  a 
  con- 
  

   tinuous 
  area 
  equal 
  in 
  geographical 
  extent 
  to 
  that 
  filled 
  by 
  the 
  

   Stinchar 
  series 
  itself. 
  The 
  ground 
  occupied 
  by 
  these 
  flagstones 
  

   extends 
  northward 
  from 
  the 
  margin 
  of 
  the 
  Benan 
  Conglomerate 
  to 
  a 
  

   line 
  of 
  fault 
  which 
  ranges 
  from 
  the 
  coast-line 
  south 
  of 
  the 
  town 
  of 
  

   Girvan 
  across 
  Saugh 
  Hill 
  inland 
  to 
  the 
  Old-Bed- 
  Sandstone 
  heights 
  

  

  