﻿PEOE. 
  C. 
  LAPWOETH 
  ON 
  THE 
  GIEVAN 
  SUCCESSION. 
  549 
  

  

  tion*. 
  At 
  the 
  same 
  time 
  the 
  existence 
  of 
  the 
  long 
  strip 
  of 
  Silurian 
  

   strata 
  near 
  Straiton 
  is 
  made 
  known 
  for 
  the 
  first 
  time, 
  and 
  a 
  well- 
  

   founded 
  suggestion 
  thrown 
  out 
  that 
  it 
  is 
  of 
  Upper 
  Silurian 
  age. 
  

  

  The 
  new 
  material 
  supplied 
  by 
  sheet 
  7 
  and 
  its 
  explanation, 
  which 
  

   bears 
  upon 
  the 
  rocks 
  of 
  the 
  great 
  plateau 
  to 
  the 
  south 
  of 
  the 
  Girvan 
  

   valley, 
  is, 
  on 
  other 
  hand, 
  comparatively 
  unimportant. 
  The 
  rocks 
  

   south 
  of 
  the 
  Stinchar 
  valley 
  are 
  described 
  as 
  of 
  Llandeilo 
  age, 
  while 
  

   the 
  strata 
  of 
  the 
  plateau 
  itself, 
  including 
  the 
  Stinchar 
  Limestones 
  

   and 
  metamorphic 
  rocks, 
  are 
  assigned 
  to 
  the 
  Caradoc, 
  with 
  the 
  du- 
  

   bious 
  exception 
  of 
  some 
  indefinable 
  patches 
  of 
  Lower 
  Llandovery. 
  

   The 
  limestone 
  of 
  the 
  region 
  is 
  said 
  to 
  occur 
  in 
  lenticular 
  patches 
  

   imbedded 
  in 
  conglomerates. 
  Beyond 
  a 
  suggestion 
  that 
  the 
  section 
  

   seen 
  upon 
  the 
  coast-line 
  near 
  Shalloch 
  is 
  a 
  synclinal 
  formf, 
  and 
  thus 
  

   corroborative 
  of 
  Murchison's 
  opinion 
  that 
  the 
  Ardwell 
  Graptolitic 
  

   flagstones 
  are 
  the 
  highest 
  visible 
  beds 
  upon 
  the 
  plateau, 
  no 
  evidence 
  

   is 
  adduced 
  of 
  an 
  ascending 
  sequence; 
  and 
  the 
  description 
  of 
  the 
  

   complicated 
  rock-structure 
  of 
  the 
  district 
  is 
  deferred 
  until 
  the 
  pub- 
  

   lication 
  of 
  the 
  neighbouring 
  sheet 
  8, 
  which 
  has 
  not 
  as 
  yet 
  (1881) 
  

   made 
  its 
  appearance. 
  

  

  This 
  deficiency, 
  however, 
  is 
  supplied 
  to 
  a 
  large 
  extent 
  by 
  Professor 
  

   Geikie's 
  section 
  of 
  the 
  rocks 
  of 
  the 
  southern 
  plateau 
  inserted 
  in 
  the 
  

   fourth 
  edition 
  of 
  ' 
  Siluria' 
  J. 
  From 
  this 
  we 
  gather 
  that 
  the 
  synclinal 
  

   recognizable 
  upon 
  the 
  shore-line 
  is 
  prolonged 
  into 
  the 
  interior 
  of 
  the 
  

   country, 
  and 
  that, 
  as 
  Murchison 
  originally 
  asserted, 
  the 
  Penwhapple 
  

   Graptolitic. 
  flagstones 
  occupy 
  its 
  centre. 
  To 
  the 
  northward 
  these 
  

   are 
  underlain 
  by 
  the 
  Pentamerus- 
  gritstones 
  and 
  pebble-beds 
  of 
  

   Camregan 
  and 
  Saugh 
  Hill. 
  The 
  area 
  of 
  Benan 
  Hill 
  and 
  of 
  

   the 
  Stinchar 
  is 
  occupied 
  by 
  a 
  massive 
  conglomerate 
  having 
  no 
  

   clear 
  relations 
  to 
  the 
  foregoing, 
  and 
  including 
  two 
  distinct 
  bands 
  of 
  

   limestone. 
  To 
  the 
  south 
  of 
  the 
  Stinchar 
  valley 
  this 
  limestone- 
  and 
  

   conglomerate-series 
  is 
  faulted 
  against 
  the 
  barren 
  greywackes 
  of 
  the 
  

   Uplands, 
  while 
  to 
  the 
  north 
  of 
  the 
  valley 
  it 
  is 
  transgressively 
  overlain 
  

   by 
  the 
  boulder-beds 
  of 
  the 
  higher 
  ridges 
  of 
  Benan 
  Hill, 
  which 
  are 
  

   assigned 
  to 
  the 
  epoch 
  of 
  the 
  Middle 
  Old 
  Eed 
  Sandstone. 
  

  

  The 
  remaining 
  publications 
  treating 
  of 
  the 
  sequence 
  of 
  the 
  Lower 
  

   Palaeozoic 
  rocks 
  of 
  Girvan 
  may 
  be 
  dismissed 
  in 
  a 
  few 
  words, 
  as 
  they 
  

   contain 
  no 
  definite 
  physical 
  evidences 
  in 
  support 
  of 
  the 
  views 
  advo- 
  

   cated 
  in 
  them. 
  In 
  1874 
  Mr. 
  D. 
  J. 
  Brown, 
  in 
  a 
  general 
  paper 
  on 
  the 
  

   Silurian 
  rocks 
  of 
  the 
  South 
  of 
  Scotland, 
  advanced 
  the 
  opinion 
  that 
  

   the 
  Caradoc 
  of 
  Girvan 
  would 
  be 
  found 
  to 
  overlie 
  the 
  Llandeilo 
  un- 
  

   conformably, 
  and 
  that 
  the 
  Mulloch-Hill 
  strata 
  are 
  the 
  only 
  beds 
  

   that 
  can 
  with 
  propriety 
  be 
  assigned 
  to 
  the 
  Llandovery 
  §. 
  

  

  In 
  1876 
  the 
  country 
  was 
  hastily 
  examined 
  by 
  myself 
  and 
  its 
  

   strata 
  noticed 
  in 
  brief 
  in 
  the 
  opening 
  chapter 
  of 
  the 
  ' 
  Catalogue 
  of 
  

   Western 
  Scottish 
  Fossils,' 
  where 
  the 
  beds 
  superior 
  to 
  the 
  Limestone 
  

   were 
  arranged 
  by 
  me 
  in 
  two 
  main 
  groups, 
  the 
  Graptolitic 
  flagstones 
  

  

  * 
  Explanation 
  Sheet 
  14, 
  Geol. 
  Survey 
  of 
  Scotland, 
  pp. 
  8 
  and 
  10. 
  

   t 
  Explanation 
  Sheet 
  7, 
  Geol. 
  Survey 
  of 
  Scotland, 
  pp. 
  1-11. 
  

   J 
  Siluria, 
  fourth 
  edition, 
  p. 
  156. 
  

   § 
  Transactions 
  Edinb. 
  Geol. 
  Society, 
  1874, 
  pp. 
  316 
  &c. 
  

  

  