﻿548 
  PK0P. 
  C. 
  LAPWORTH 
  OX 
  THE 
  GKTRVAX 
  SUCCESSION. 
  

  

  palaeontoiogically, 
  as 
  believed 
  by 
  Murchison, 
  with 
  the 
  Balaformation*, 
  

   but 
  actually 
  formed 
  the 
  base 
  of 
  Murchison's 
  Upper 
  Silurian 
  system. 
  

   This 
  was 
  soon 
  followed 
  by 
  Murchison's 
  erection 
  of 
  the 
  Pentamerus- 
  

   bearing 
  strata 
  into 
  the 
  transitional 
  formation 
  of 
  the 
  Llandovery, 
  and 
  

   the 
  extension 
  of 
  this 
  improved 
  classification 
  to 
  the 
  corresponding 
  

   strata 
  outside 
  the 
  typical 
  areas. 
  

  

  In 
  1867 
  appeared 
  the 
  fourth 
  edition 
  of 
  Murchison's' 
  Siluria 
  f, 
  in 
  

   which 
  the 
  veteran 
  geologist 
  incorporated 
  and 
  systematized 
  these 
  

   and 
  other 
  advances 
  in 
  the 
  classification 
  of 
  the 
  Lower 
  Palaeozoic 
  rocks 
  

   necessitated 
  by 
  the 
  results 
  of 
  the 
  researches 
  of 
  the 
  officers 
  of 
  the 
  

   Survey 
  under 
  his 
  direction 
  and 
  their 
  amateur 
  contemporaries. 
  In 
  

   this 
  work 
  these 
  Girvan 
  strata 
  are 
  noticed 
  in 
  some 
  detail 
  ; 
  and, 
  

   assisted 
  by 
  Professor 
  A. 
  Geikie, 
  Murchison 
  attempted 
  a 
  more 
  de- 
  

   tailed 
  correlation 
  than 
  that 
  suggested 
  in 
  his 
  earlier 
  memoir. 
  But, 
  

   though 
  not 
  expressly 
  advocated 
  in 
  words, 
  the 
  same 
  general 
  order 
  

   of 
  succession 
  is 
  retained 
  unmodified, 
  except 
  that 
  the 
  higher 
  beds 
  are 
  

   referred 
  to 
  the 
  newly 
  instituted 
  formation 
  of 
  the 
  Llandovery, 
  and 
  

   are 
  described 
  as 
  indicating 
  a 
  passage 
  into 
  the 
  base 
  of 
  the 
  Upper 
  

   Silurian. 
  

  

  Confirmed 
  in 
  his 
  original 
  views 
  of 
  the 
  general 
  order 
  of 
  succession 
  

   in 
  this 
  region 
  by 
  the 
  new 
  data 
  supplied 
  to 
  him 
  by 
  Professor 
  Geikie, 
  

   Murchison 
  again 
  confounded 
  the 
  two 
  distinct 
  faunas 
  of 
  the 
  shelly 
  

   sandstones 
  of 
  Mulloch 
  II 
  ill 
  on 
  the 
  north 
  of 
  the 
  Girvan 
  valley 
  and 
  

   the 
  Penta 
  ui 
  ervs-gnt 
  stones 
  of 
  Saugh 
  Hill 
  on 
  the 
  south, 
  and 
  placed 
  

   the 
  much 
  older 
  fauna 
  of 
  the 
  Ardwell 
  and 
  Penwhapple 
  flagstones 
  

   above 
  both. 
  Nevertheless 
  he 
  recognized 
  most 
  distinctly 
  the 
  hetero- 
  

   geneous 
  character 
  of 
  the 
  fauua 
  of 
  his 
  middle 
  group, 
  and 
  accounted 
  

   for 
  it 
  on 
  the 
  theory 
  that 
  here 
  " 
  as 
  in 
  England 
  and 
  Wales, 
  particu- 
  

   larly 
  as 
  we 
  ascend 
  the 
  series, 
  we 
  meet 
  with 
  rocks 
  in 
  which 
  the 
  upper 
  

   and 
  lower 
  types 
  of 
  fossils 
  arc 
  mixed 
  together 
  "J. 
  

  

  In 
  the 
  following 
  year 
  Professor 
  A.Geikie§ 
  published 
  a 
  brief 
  resume 
  

   of 
  the 
  conclusions 
  already 
  reached 
  by 
  geologists 
  respecting 
  the 
  

   sequence 
  in 
  the 
  Girvan 
  area, 
  pointing 
  out 
  with 
  great 
  clearness 
  and 
  

   effect 
  the 
  tantalizing 
  nature 
  of 
  the 
  evidences 
  obtainable 
  in 
  the 
  

   district. 
  

  

  In 
  1869 
  the 
  detailed 
  examination 
  of 
  the 
  strata 
  of 
  the 
  region 
  by 
  

   the 
  officers 
  of 
  the 
  Geological 
  Survey 
  having 
  been 
  completed, 
  sheets 
  

   7 
  and 
  14 
  of 
  the 
  one-inch 
  maps 
  of 
  the 
  district 
  were 
  issued 
  to 
  the 
  

   public, 
  accompanied 
  by 
  brief 
  explanatory 
  memoirs. 
  

  

  In 
  sheet 
  14 
  and 
  its 
  accompanying 
  explanation 
  we 
  are 
  presented 
  

   with 
  much 
  that 
  is 
  new 
  and 
  of 
  great 
  value. 
  The 
  anticlinal 
  disposition 
  

   of 
  the 
  strata 
  of 
  the 
  Mulloch-Hill 
  inlier 
  is 
  shown 
  with 
  great 
  distinct- 
  

   ness 
  ; 
  the 
  superposition 
  of 
  the 
  Mulloch-Hill 
  sandstones 
  to 
  the 
  

   I 
  1 
  ri 
  nucleus-shales 
  of 
  Drummuck 
  established 
  beyond 
  dispute 
  ; 
  while 
  

   a 
  sufficiency 
  of 
  palaeontological 
  evidence 
  is 
  adduced 
  to 
  make 
  it 
  evident 
  

   that 
  the 
  former 
  appertain 
  to 
  some 
  portion 
  of 
  the 
  Llandovery 
  forma- 
  

  

  * 
  Phil. 
  Mag. 
  ser. 
  4, 
  vol. 
  viii. 
  p. 
  301. 
  

  

  t 
  Siluria, 
  4th 
  edit. 
  1867, 
  pp. 
  155-158. 
  

  

  j 
  Siluria, 
  4th 
  edit. 
  p. 
  157. 
  

  

  § 
  Transactions 
  Geological 
  Society 
  of 
  Glasgow, 
  vol. 
  iii. 
  p. 
  74. 
  

  

  