﻿PROF. 
  C. 
  LAPWORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  659 
  

  

  Generalized 
  Section 
  of 
  the 
  Dailly 
  Series. 
  

  

  Straiton 
  beds, 
  

   900 
  ft. 
  

  

  Upper 
  Dailly. 
  ■{ 
  

  

  (Straiton 
  Grits 
  and 
  Conglomerate. 
  

   Blair 
  Shales 
  ( 
  Vomerinus-beds). 
  

   Druinyork 
  olive-coloured 
  Flags. 
  

  

  Dailly 
  

   Series, 
  , 
  

  

  2600 
  ) 
  

  

  feet, 
  

  

  Bargany 
  beds, 
  ] 
  Blackwood 
  Flags. 
  

  

  700 
  ft. 
  J 
  Glenfoot 
  Flags 
  and 
  Shales. 
  

  

  Lowe 
  

  

  t. 
  . 
  n 
  f 
  Penkill 
  beds, 
  

   DaiU 
  y- 
  J 
  1000 
  ft. 
  

  

  f 
  Gyrtograptus-Grayi 
  naudstones, 
  

  

  J 
  Penkill 
  Greywackes. 
  

  

  j 
  Protovir?/ularia-Q.8Lgs. 
  

  

  [_ 
  Crossopodia- 
  or 
  Purple 
  Shales. 
  

  

  (F) 
  Summary 
  op 
  the 
  foregoing 
  Evidences 
  and 
  Conclusions 
  

  

  RESPECTING 
  THE 
  STRATIGRAPHY 
  OF 
  THE 
  GlRVAN 
  SUCCESSION. 
  

  

  ' 
  (1) 
  In 
  the 
  foregoing 
  pages 
  I 
  have 
  laid 
  before 
  the 
  reader 
  all 
  the 
  more 
  

   important 
  data 
  obtainable 
  in 
  the 
  geographical 
  area 
  under 
  examination 
  

   which 
  bear 
  upon 
  the 
  main 
  question 
  of 
  the 
  natural 
  order 
  of 
  the 
  

   Lower 
  Palaeozoic 
  rocks 
  of 
  the 
  Girvan 
  region. 
  The 
  original 
  arrange- 
  

   ment 
  of 
  the 
  beds 
  themselves 
  has 
  been 
  so 
  frequently 
  interrupted 
  by 
  

   profound 
  dislocations, 
  and 
  has'been 
  rendered 
  so 
  dubious 
  locally 
  by 
  

   perplexing 
  folds 
  and 
  inversions, 
  that 
  the 
  task 
  of 
  reducing 
  them 
  to 
  

   their 
  natural 
  order 
  has 
  been 
  one 
  of 
  far 
  more 
  than 
  ordinary 
  difficulty. 
  

   But 
  so 
  well 
  are 
  the 
  several 
  subformations 
  in 
  the 
  collective 
  series 
  

   individualized 
  by 
  distinct 
  petrological 
  features, 
  that 
  the 
  field-geologist 
  

   has 
  generally 
  little 
  hesitation 
  in 
  recognizing 
  their 
  entangled 
  or 
  dis- 
  

   located 
  fragments 
  at 
  a 
  glance. 
  At 
  the 
  same 
  time 
  also 
  the 
  foldings 
  and 
  

   inversions 
  of 
  the 
  strata 
  prevail 
  only 
  in 
  certain 
  definite 
  geographical 
  

   subareas, 
  where 
  they 
  can 
  usually 
  be 
  ultimately 
  detected 
  and 
  allowed 
  

   for. 
  Finally, 
  the 
  greater 
  faults 
  are, 
  as 
  a 
  rule, 
  by 
  no 
  means 
  difficult 
  

   of 
  localization, 
  owing 
  to 
  the 
  fact 
  that 
  they 
  bring 
  into 
  abrupt 
  and 
  

   unnatural 
  collocation 
  upon 
  the 
  ground 
  strata 
  very 
  distinct 
  in 
  their 
  

   lithological 
  and 
  palceontological 
  features. 
  

  

  Nevertheless 
  the 
  complexities 
  and 
  difficulties 
  of 
  the 
  stratigraphy 
  

   of 
  the 
  fossiliferous 
  rocks 
  of 
  the 
  Girvan 
  region 
  are 
  so 
  great 
  that 
  the 
  

   solution 
  of 
  the 
  problem 
  of 
  their 
  natural 
  sequence 
  has 
  been 
  only 
  

   arrived 
  at 
  by 
  the 
  accumulation 
  of 
  an 
  excessive 
  amount 
  of 
  evidence 
  

   collected 
  in 
  the 
  field. 
  This 
  evidence, 
  however, 
  is 
  now 
  so 
  full, 
  and 
  so 
  

   conclusive, 
  that 
  there 
  can 
  be 
  no 
  longer 
  any 
  doubt 
  of 
  the 
  natural 
  

   petrological 
  subdivisions 
  of 
  the 
  strata 
  of 
  the 
  Girvan 
  rocks, 
  or 
  of 
  their 
  

   true 
  positions 
  in 
  the 
  ascending 
  succession. 
  

  

  (2) 
  The 
  physical 
  evidence, 
  as 
  developed 
  in 
  the 
  preceding 
  pages, 
  

   in 
  support 
  of 
  our 
  conclusions 
  may 
  be 
  summarized 
  as 
  follows 
  : 
  — 
  

  

  (i) 
  Selecting 
  the 
  remarkable 
  Benan-Hill 
  Conglomerate 
  as 
  our 
  

   primary 
  horizon 
  of 
  reference, 
  we 
  discover 
  that 
  it 
  is 
  merely 
  the 
  

   central 
  member 
  of 
  a 
  series 
  (the 
  Barr 
  Series) 
  of 
  boulder-beds 
  and 
  

   conglomerates, 
  with 
  intercalary 
  zones 
  of 
  limestone 
  and 
  fossiliferous 
  

   shales. 
  This 
  series 
  exhibits 
  proofs 
  of 
  the 
  most 
  perfect 
  conformity 
  

   from 
  base 
  to 
  summit, 
  and 
  its 
  various 
  members 
  admit 
  of 
  minute 
  and 
  

  

  