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  PROF. 
  C. 
  LAPWORTH 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  and 
  that 
  their 
  present 
  steep 
  dip 
  is 
  owing 
  to 
  the 
  intercalary 
  fault 
  we 
  

   have 
  referred 
  to. 
  This 
  fault, 
  however, 
  while 
  it 
  has 
  permitted 
  these 
  

   overlying 
  beds 
  to 
  be 
  crushed 
  into 
  a 
  general 
  correspondence 
  in 
  incli- 
  

   nation 
  with 
  the 
  underlying 
  strata, 
  has 
  not 
  actually 
  allowed 
  of 
  their 
  

   removal 
  far 
  from 
  their 
  origiual 
  position, 
  the 
  angular 
  fragments 
  in- 
  

   cluded 
  in 
  the 
  sandstones 
  being 
  primarily 
  derived 
  from 
  the 
  striped 
  

   shales 
  with 
  which 
  they 
  are 
  still 
  in 
  contact. 
  

  

  This 
  quartz 
  conglomerate 
  is, 
  in 
  all 
  likelihood, 
  identical 
  with 
  a 
  

   similar 
  band 
  which 
  is 
  found 
  at 
  the 
  base 
  of 
  the 
  Saugh-Hill 
  rocks, 
  

   running 
  from 
  the 
  head 
  of 
  Saugh-Hill 
  Burn 
  to 
  the 
  eastern 
  slopes 
  of 
  

   Camregan 
  Hill. 
  It 
  is 
  there 
  divided 
  from 
  the 
  striped 
  and 
  grey 
  

   shales 
  of 
  the 
  DipJograptus-modestus 
  beds 
  by 
  a 
  narrow 
  strip 
  of 
  flaggy 
  

   greywackes 
  with 
  Climacograptus 
  normalis. 
  (See 
  Map, 
  PL 
  XXV. 
  1, 
  

   and 
  Section, 
  fig. 
  25.) 
  

  

  Turning 
  next 
  to 
  the 
  neighbouring 
  Graptolitic 
  shales 
  and 
  associated 
  

   strata 
  of 
  Shalloch 
  Forge, 
  and 
  bearing 
  in 
  mind 
  the 
  fact 
  of 
  the 
  

   fault 
  and 
  possible 
  unconformity 
  between 
  them 
  and 
  the 
  conglo- 
  

   meratic 
  sandstones, 
  we 
  find 
  that 
  they 
  present 
  us 
  with 
  no 
  further 
  

   difficulty. 
  The 
  observer 
  who 
  has 
  made 
  himself 
  familiar 
  with 
  the 
  

   section 
  of 
  the 
  Saugh-Hill 
  shales 
  and 
  gritstones 
  in 
  Penwhapple 
  Glen 
  

   will 
  at 
  once 
  refer 
  the 
  striped 
  shales 
  here 
  exhibited 
  to 
  the 
  zone 
  of 
  

   striped 
  shales 
  in 
  the 
  immediate 
  neighbourhood 
  of 
  the 
  great 
  fault 
  of 
  

   Penwhapple 
  ; 
  for 
  not 
  only 
  are 
  the 
  strata 
  lithologically 
  similar 
  in 
  the 
  

   two 
  localities, 
  but 
  their 
  fossils 
  are 
  absolutely 
  identical 
  species 
  for 
  

   species. 
  

  

  The 
  underlying 
  Penwhapple 
  zone 
  of 
  black 
  mudstone 
  should 
  here 
  

   be 
  found 
  in 
  the 
  blank 
  which 
  intervenes 
  between 
  the 
  striped 
  shales 
  

   and 
  the 
  Coralline 
  limestone 
  with 
  Pentamerus, 
  which 
  latter 
  affords 
  

   an 
  additional 
  link 
  of 
  correspondence 
  with 
  the 
  Penwhapple 
  section, 
  

   where 
  we 
  find 
  the 
  merest 
  fragment 
  of 
  the 
  Coralline 
  seam 
  in 
  the 
  

   lowest 
  concretionary 
  rock 
  with 
  Pentamerus 
  and 
  Corals. 
  

  

  In 
  the 
  Saugh-Hill 
  section 
  of 
  Penwhapple 
  this 
  Coralline 
  seam 
  is 
  the 
  

   lowest 
  rock 
  exposed 
  ; 
  but 
  if 
  no 
  hidden 
  fault 
  intervene 
  between 
  the 
  

   bed, 
  as 
  here 
  exhibited, 
  and 
  the 
  coarse 
  Horse-Rock 
  conglomerate, 
  we 
  

   are 
  here 
  enabled 
  to 
  descend 
  much 
  lower 
  in 
  the 
  succession, 
  and 
  to 
  

   provisionally 
  locate 
  the 
  boulder- 
  beds 
  of 
  the 
  Horse 
  Rock 
  immediately 
  

   below 
  the 
  base 
  of 
  the 
  Penwhapple 
  and 
  Saugh-Hill 
  sections, 
  and 
  im- 
  

   mediately 
  subjacent 
  to 
  the 
  Coralline 
  or 
  Pentamerus-b&nd. 
  

  

  2. 
  Craigskelly. 
  — 
  The 
  boulder-bed 
  of 
  the 
  Horse 
  Rock 
  is 
  prolonged 
  

   south-westward 
  into 
  the 
  long 
  mound-like 
  boss 
  of 
  Craigskelly. 
  This 
  

   forms 
  a 
  low 
  rugged 
  island 
  at 
  high 
  water, 
  but 
  is 
  connected 
  with 
  the 
  

   shore 
  by 
  a 
  sandy 
  beach 
  at 
  low 
  states 
  of 
  the 
  tide. 
  The 
  coarse 
  strata 
  

   of 
  the 
  Horse 
  Rock 
  are 
  here 
  perpendicular 
  in 
  attitude, 
  and 
  have 
  a 
  

   transverse 
  diameter 
  at 
  least 
  double 
  that 
  they 
  possess 
  in 
  the 
  former 
  

   locality. 
  The 
  boulder-beds 
  already 
  described 
  occupy 
  the 
  south- 
  

   eastern 
  half 
  of 
  the 
  island 
  ; 
  while 
  all 
  the 
  western 
  half 
  is 
  formed 
  of 
  

   hard-bedded 
  gritstones 
  several 
  feet 
  in 
  thickness, 
  plunging 
  suddenly 
  

   downwards 
  into 
  deep 
  water. 
  These 
  gritstones 
  weather 
  to 
  a 
  yellowish 
  

   tint, 
  and 
  a 
  few 
  have 
  the 
  peculiar 
  pink 
  tinge 
  which 
  marks 
  many 
  of 
  

   the 
  rocks 
  of 
  Saugh 
  Hill, 
  with 
  which 
  also 
  they 
  agree 
  in 
  the 
  pale 
  grey 
  

  

  