﻿658 
  PROF. 
  C. 
  LA.PWORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  West 
  of 
  the 
  village 
  of 
  Straiton 
  the 
  terminal 
  beds 
  of 
  this 
  flaggy 
  

   zone 
  are 
  succeeded 
  in 
  the 
  hillocks 
  south 
  of 
  the 
  roadside 
  by 
  a 
  most 
  

   peculiar 
  set 
  of 
  strata, 
  consisting 
  of 
  purple 
  and 
  grey 
  conglomeratic 
  

   greywacke 
  and 
  flagstone, 
  of 
  great 
  hardness 
  and 
  toughness. 
  The 
  

   matrix 
  of 
  the 
  chief 
  grit 
  or 
  conglomerate 
  band 
  is 
  purple, 
  and 
  is 
  

   more 
  or 
  less 
  sandy 
  in 
  character, 
  reminding 
  us 
  of 
  the 
  red 
  conglo- 
  

   merate 
  at 
  the 
  base 
  of 
  the 
  Mulloch-Hill 
  Sandstone. 
  It 
  is 
  interbedded 
  

   with 
  blue 
  mudstones 
  aud 
  olive-green 
  flaggy 
  shales. 
  These 
  beds 
  are 
  

   all 
  wholly 
  destitute 
  of 
  fossils, 
  but 
  form 
  together 
  a 
  most 
  distinctive 
  

   physical 
  assemblage. 
  

  

  The 
  same 
  zone 
  of 
  purple 
  flagstone 
  and 
  conglomerate 
  is 
  found 
  in 
  

   precisely 
  the 
  same 
  stratigraphical 
  position 
  along 
  the 
  line 
  of 
  strike 
  

   two 
  miles 
  to 
  the 
  westward, 
  where 
  it 
  is 
  shown 
  in 
  some 
  old 
  quarries 
  

   near 
  the 
  roadway 
  between 
  Knockgardner 
  and 
  Kirkbride. 
  

  

  At 
  both 
  these 
  localities 
  this 
  Straiton 
  gritstone 
  band 
  is 
  followed 
  

   unconformably 
  by 
  the 
  overlying 
  Carboniferous 
  rocks 
  of 
  the 
  Girvan 
  

   valley, 
  thus 
  forming 
  the 
  outer 
  and 
  final 
  member 
  of 
  the 
  entire 
  

   Lower 
  Palaeozoic 
  series 
  of 
  this 
  region. 
  To 
  the 
  west 
  of 
  Straiton 
  itself 
  

   the 
  southern 
  margin 
  of 
  the 
  Carboniferous 
  rocks 
  creeps 
  down 
  upon 
  

   the 
  Bargany 
  fault, 
  and 
  the 
  Silurian 
  is 
  finally 
  buried 
  from 
  sight 
  by 
  

   the 
  unconformably 
  overlying 
  strata 
  of 
  Upper 
  Palaeozoic 
  age. 
  

  

  It 
  is 
  evident 
  from 
  the 
  foregoing 
  descriptions 
  that 
  the 
  whole 
  of 
  the 
  

   strata 
  found 
  in 
  the 
  long 
  strip 
  of 
  Silurian 
  country 
  extending 
  from 
  the 
  

   Braehill 
  near 
  Girvan 
  to 
  the 
  village 
  of 
  Straiton, 
  and 
  forming 
  the 
  

   northern 
  slope 
  of 
  the 
  plateau 
  lying 
  to 
  the 
  south 
  of 
  Girvan 
  valley, 
  

   belong 
  to 
  one 
  and 
  the 
  same 
  general 
  physical 
  series. 
  To 
  this 
  series, 
  

   which 
  we 
  term 
  the 
  Dailly 
  Series, 
  after 
  the 
  parish 
  in 
  which 
  its 
  strata 
  

   are 
  most 
  perfectly 
  developed 
  in 
  this 
  region, 
  must 
  clearly 
  be 
  as- 
  

   signed 
  the 
  highest 
  place 
  among 
  the 
  four 
  natural 
  divisions 
  of 
  the 
  

   Girvan 
  succession, 
  for 
  it 
  follows 
  the 
  third 
  or 
  Newlands 
  division 
  in 
  

   the 
  geographical 
  order 
  of 
  the 
  deposits 
  of 
  the 
  region, 
  and 
  graduates 
  

   therefrom 
  in 
  its 
  lithological 
  characters. 
  Its 
  strata 
  dip 
  either 
  perpen- 
  

   dicularly 
  or 
  at 
  steep 
  angles 
  to 
  the 
  southward, 
  as 
  if 
  to 
  pass 
  under 
  this 
  

   third 
  or 
  Newlands 
  series. 
  But 
  not 
  only 
  is 
  their 
  superiority 
  in 
  strati- 
  

   graphical 
  position 
  to 
  be 
  inferred 
  from 
  the 
  fact 
  already 
  demonstrated 
  

   that 
  the 
  strata 
  north 
  of 
  the 
  Knockgerran 
  fault 
  are 
  generally 
  inverted, 
  

   but 
  it 
  is 
  placed 
  wholly 
  beyond 
  question 
  by 
  the 
  evidence 
  of 
  the 
  fossils. 
  

   This 
  inversion, 
  then, 
  being 
  admitted 
  for 
  the 
  series 
  as 
  a 
  whole, 
  it 
  is 
  to 
  be 
  

   expected 
  that 
  there 
  is 
  actually 
  to 
  be 
  found 
  an 
  ascending 
  order 
  among 
  

   the 
  beds 
  as 
  we 
  depart 
  northward 
  from 
  the 
  Camregan 
  grits, 
  which 
  

   form 
  the 
  highest 
  band 
  of 
  the 
  Saugh-Hill 
  series 
  in 
  the 
  direction 
  of 
  the 
  

   Bargany 
  fault 
  and 
  the 
  unconformably 
  overlying 
  Carboniferous. 
  We 
  

   have 
  seen 
  that 
  there 
  can 
  be 
  no 
  dislocation 
  of 
  importance 
  in 
  any 
  of 
  

   the 
  sections 
  capable 
  of 
  study, 
  the 
  beds 
  followiug 
  each 
  other 
  with 
  

   great 
  regularity 
  in 
  parallel 
  zones, 
  which 
  graduate 
  almost 
  insensibly 
  

   the 
  one 
  into 
  the 
  other. 
  Reserving 
  therefore 
  the 
  palaeontological 
  

   arguments 
  in 
  support 
  of 
  these 
  views 
  to 
  the 
  succeeding 
  part 
  of 
  this 
  

   memoir, 
  we 
  are 
  justified 
  in 
  the 
  presumption 
  that 
  the 
  Dailly 
  Series 
  

   consists 
  of 
  the 
  following 
  groups 
  in 
  descending 
  order 
  : 
  — 
  

  

  