﻿PEOP. 
  C. 
  LAPWOETH 
  ON 
  THE 
  GIEVAN 
  SUCCESSION. 
  553 
  

  

  fragments 
  of 
  hardened 
  rocks, 
  sandstones, 
  and 
  greywackes. 
  These 
  

   are 
  all 
  intermingled 
  confusedly 
  together 
  in 
  a 
  sandy 
  or 
  ashy 
  paste, 
  

   composed 
  of 
  the 
  same 
  materials 
  as 
  the 
  included 
  pebbles, 
  and 
  usually 
  

   of 
  a 
  dull 
  greenish 
  colour, 
  but 
  occasionally 
  purple 
  and 
  sometimes 
  

   almost 
  black. 
  All 
  the 
  included 
  blocks 
  are 
  well 
  rounded 
  and 
  smoothed 
  

   by 
  aqueous 
  action 
  ; 
  angular 
  chips 
  are 
  extremely 
  rare, 
  and 
  the 
  grains 
  

   of 
  the 
  matrix 
  itself, 
  except 
  when 
  distinctly 
  ashy 
  and 
  crystalline, 
  bear 
  

   evidence, 
  in 
  their 
  rounded 
  forms, 
  of 
  long- 
  continued 
  attrition 
  by 
  

   v 
  water. 
  

  

  The 
  physical 
  geologist 
  who 
  attempts 
  the 
  study 
  of 
  this 
  area 
  finds, 
  

   scattered 
  confusedly 
  over 
  the 
  surface 
  of 
  the 
  ridge, 
  patches 
  of 
  lime- 
  

   stones 
  and 
  calcareous 
  shales, 
  trenchantly 
  individualized 
  by 
  many 
  

   well-marked 
  lithological 
  peculiarities, 
  but 
  having 
  the 
  most 
  enig- 
  

   matical 
  relations 
  with 
  respect 
  to 
  the 
  surrounding 
  conglomerates. 
  

   In 
  their 
  topographical 
  distribution 
  these 
  calcareous 
  rocks 
  at 
  first 
  

   sight 
  appear 
  most 
  capricious. 
  In 
  one 
  locality 
  an 
  interrupted 
  line 
  

   of 
  exposures 
  of 
  these 
  peculiar 
  beds 
  can 
  be 
  traced 
  for 
  some 
  distance 
  ; 
  

   but 
  suddenly 
  it 
  dies 
  out 
  in 
  the 
  most 
  unexpected 
  manner 
  ; 
  and 
  in 
  

   the 
  direction 
  in 
  which 
  we 
  should 
  naturally 
  expect 
  its 
  prolongation 
  

   we 
  find, 
  instead, 
  the 
  great 
  conglomerate 
  extending 
  continuous 
  and 
  

   unbroken. 
  Nor 
  do 
  the 
  many 
  sporadic 
  sections 
  of 
  these 
  calcareous 
  

   beds 
  seem 
  to 
  possess 
  any 
  definite 
  characteristics 
  in 
  common 
  that 
  

   would 
  allow 
  of 
  their 
  being 
  paralleled 
  in 
  detail 
  and 
  brought 
  into 
  any 
  

   thing 
  like 
  intelligible 
  interrelationships 
  among 
  themselves. 
  In 
  one 
  

   spot 
  we 
  find 
  a 
  mass 
  of 
  flaggy 
  limestone 
  50 
  feet 
  in 
  thickness, 
  without 
  

   a 
  trace 
  of 
  other 
  fossiliferous 
  strata 
  ; 
  in 
  a 
  second, 
  a 
  similar 
  thickness 
  

   of 
  calcareous 
  shales 
  bears 
  it 
  company 
  ; 
  in 
  a 
  third, 
  shelly 
  sandstones 
  

   and 
  grits 
  are 
  also 
  present 
  in 
  force. 
  But 
  while 
  no 
  two 
  consecutive 
  

   exposures 
  offer 
  us 
  a 
  succession 
  precisely 
  similar 
  among 
  the 
  beds 
  

   distinct 
  from 
  the 
  great 
  conglomerate, 
  they 
  all 
  agree 
  in 
  the 
  one 
  fact 
  

   that 
  both 
  above 
  and 
  below 
  them 
  the 
  great 
  conglomerate 
  itself 
  is 
  

   seen 
  in 
  force 
  with 
  all 
  its 
  characteristic 
  features, 
  its 
  gentle 
  dip, 
  and 
  

   persistent 
  N.E. 
  and 
  S.W. 
  strike. 
  

  

  Nor 
  are 
  these 
  the 
  only 
  difficulties. 
  In 
  some 
  spots 
  the 
  conglo- 
  

   merate 
  is 
  separated 
  from 
  the 
  flaggy 
  limestones 
  by 
  several 
  feet 
  of 
  

   concretionary 
  shales 
  ; 
  while 
  in 
  other 
  spots 
  not 
  a 
  trace 
  of 
  these 
  shales 
  

   is 
  visible, 
  but 
  in 
  their 
  place 
  the 
  strata 
  afford 
  proof 
  of 
  an 
  apparent 
  

   unconformability. 
  Boulders 
  and 
  nodules 
  of 
  the 
  limestone 
  are 
  found 
  

   in 
  the 
  lowest 
  beds 
  of 
  the 
  immediately 
  overlying 
  conglomerate 
  ; 
  and 
  

   the 
  latter 
  seems 
  to 
  repose 
  irregularly 
  in 
  the 
  hollows 
  of 
  the 
  eroded 
  

   upper 
  face 
  of 
  the 
  limestone 
  itself. 
  

  

  Kecognizing 
  these 
  complexities, 
  and 
  impressed 
  mainly 
  by 
  the 
  

   two 
  grand 
  facts 
  of 
  the 
  interrupted 
  nature 
  of 
  the 
  calcareous 
  beds 
  

   and 
  the 
  apparent 
  erosion 
  at 
  their 
  summit, 
  the 
  officers 
  of 
  the 
  Geological 
  

   Survey, 
  after 
  mapping 
  this 
  subdistrict, 
  adopted 
  the 
  only 
  conclusion 
  

   that 
  seemed 
  open 
  to 
  them, 
  and 
  taught 
  originally 
  that 
  the 
  limestones 
  

   were 
  irregular 
  and 
  sporadic 
  phenomena, 
  that 
  they 
  were 
  imbedded 
  

   in 
  the 
  great 
  conglomerate, 
  and 
  that 
  the 
  combined 
  mass 
  was 
  trans- 
  

   gressively 
  overlain 
  by 
  a 
  second 
  conglomerate, 
  which, 
  to 
  judge 
  from 
  

   its 
  gentle 
  inclination, 
  was 
  probably 
  of 
  Old 
  Red 
  Sandstone 
  age. 
  When 
  

  

  Q.J.G.S. 
  No. 
  152. 
  2p 
  

  

  