﻿Vol. 
  53.] 
  XEAR 
  BUNMAHON, 
  CO. 
  WATERFORD. 
  281 
  

  

  side 
  of 
  the 
  zigzag 
  path 
  down 
  the 
  cliff3 
  they 
  are 
  of 
  fine 
  red 
  sandstone 
  

   and 
  shale, 
  while 
  nearer 
  the 
  point 
  thin 
  bands 
  of 
  conglomerate 
  come 
  

   in, 
  of 
  varying 
  degrees 
  of 
  coarseness, 
  but 
  mostly 
  composed 
  of 
  small 
  

   rounded 
  pebbles. 
  Thin 
  layers 
  of 
  shale, 
  4 
  to 
  5 
  inches 
  thick, 
  

   occur 
  in 
  the 
  conglomerates. 
  

  

  The 
  larger 
  pebbles 
  of 
  the 
  conglomerates 
  are 
  subangular 
  or 
  

   angular 
  in 
  shape, 
  and 
  only 
  the 
  smaller 
  ones 
  are 
  usually 
  rounded 
  ; 
  

   they 
  consist 
  of 
  white 
  and 
  red 
  vein-quartz, 
  liver-coloured 
  quartzite, 
  

   and 
  occasionally 
  of 
  felsites 
  and 
  other 
  igneous 
  rocks. 
  The 
  beds 
  at 
  

   the 
  point 
  are 
  of 
  coarser 
  conglomerate 
  ; 
  but 
  the 
  reefs 
  and 
  stacks 
  off 
  

   the 
  point 
  are 
  composed 
  of 
  a 
  felsitic 
  rock 
  — 
  an 
  ' 
  epidotic 
  felstone 
  ' 
  

   according 
  to 
  the 
  Survey 
  Memoir 
  — 
  which 
  is 
  separated 
  by 
  a 
  fault 
  from 
  

   the 
  red 
  beds, 
  as 
  at 
  St. 
  John's 
  Island. 
  Thus 
  again 
  in 
  this 
  locality 
  

   we 
  see 
  the 
  complete 
  independence 
  of 
  the 
  red 
  beds 
  and 
  their 
  sharp 
  

   demarcation 
  from 
  the 
  surrounding 
  igneous 
  rocks. 
  

  

  Passing 
  along 
  the 
  coast 
  and 
  crossing 
  the 
  Bunmahon 
  River 
  we 
  

   fail 
  to 
  find 
  any 
  trace 
  of 
  the 
  red 
  beds 
  until 
  we 
  come 
  to 
  the 
  little 
  bay 
  

   below 
  the 
  now 
  deserted 
  engine-house 
  and 
  ore-yard 
  of 
  the 
  Knock- 
  

   mahon 
  copper-mines. 
  Here, 
  on 
  the 
  top 
  of 
  the 
  cliffs 
  by 
  the 
  engine- 
  

   house, 
  the 
  same 
  type 
  of 
  conglomerate 
  is 
  found 
  as 
  at 
  Kennedy's 
  

   Island, 
  but 
  it 
  is 
  composed 
  of 
  rather 
  larger 
  pebbles 
  and 
  angular 
  frag- 
  

   ments. 
  At 
  the 
  mouth 
  of 
  the 
  shaft 
  it 
  is 
  seen 
  to 
  dip 
  to 
  the 
  north- 
  

   west 
  at 
  about 
  45°, 
  and 
  is 
  underlain 
  by 
  fine 
  red 
  sandstone 
  resting 
  

   nn 
  conformably 
  at 
  the 
  top 
  of 
  the 
  cliff 
  upon 
  an 
  intrusive 
  rock 
  which 
  

   forms 
  all 
  the 
  lower 
  portion 
  of 
  the 
  cliff. 
  The 
  junction 
  of 
  the 
  two 
  is 
  

   now 
  inaccessible, 
  and 
  I 
  was 
  not 
  able 
  to 
  determine 
  whether 
  it 
  was 
  a 
  

   fault, 
  but 
  no 
  basal 
  breccia 
  was 
  visible, 
  and 
  I 
  am 
  inclined 
  to 
  think 
  

   that 
  a 
  fault 
  must 
  exist. 
  The 
  ore-bearing 
  lodes 
  and 
  quartz-veins 
  in 
  

   the 
  igneous 
  rocks 
  are 
  seen 
  to 
  end 
  abruptly 
  against 
  the 
  red 
  sandstones 
  

   and 
  conglomerates. 
  Mr. 
  Hodgson 
  Holdsworth 
  (op. 
  cit.) 
  states 
  that 
  

   on 
  the 
  eastern 
  side 
  of 
  Bunmahon 
  Bay 
  the 
  conglomerate 
  and 
  ' 
  red 
  

   slate' 
  underlie 
  the 
  rocks 
  of 
  the 
  coast 
  and 
  run 
  in 
  a 
  N.W.-S.E. 
  

   direction, 
  and 
  that 
  they 
  are 
  thought 
  to 
  disrupt 
  or 
  heave 
  the 
  principal 
  

   lode. 
  But 
  in 
  one 
  shaft, 
  at 
  a 
  depth 
  of 
  10 
  fathoms, 
  the 
  same 
  beds 
  

   were 
  pierced 
  as 
  those 
  which 
  are 
  exposed 
  on 
  Kennedy's 
  Island. 
  

   Kinahan, 
  however, 
  says 
  in 
  his 
  ' 
  Geology 
  of 
  Ireland 
  ' 
  (p. 
  28) 
  that 
  

   Mr. 
  Hore, 
  of 
  the 
  Bunmahon 
  mines, 
  proved 
  that 
  the 
  red 
  beds 
  and 
  

   conglomerates 
  are 
  of 
  later 
  age 
  than 
  the 
  s 
  Cambro- 
  Silurian 
  ' 
  rocks 
  

   of 
  Knockmahon, 
  and 
  lie 
  unconformably 
  upon 
  them, 
  and 
  that 
  the 
  

   lodes 
  in 
  the 
  latter 
  rocks 
  are 
  cut 
  off 
  by 
  the 
  conglomerates. 
  What 
  

   is 
  now 
  visible 
  on 
  the 
  cliffs 
  of 
  Knockmahon 
  corroborates 
  this 
  state- 
  

   ment. 
  The 
  Geological 
  Survey 
  Memoir 
  ! 
  also 
  mentions 
  the 
  fact 
  that 
  

   both 
  the 
  Stage 
  Lode 
  at 
  Knockmahon 
  and 
  the 
  Trawnamoe 
  Lode 
  west 
  

   of 
  Bunmahon 
  were 
  lost 
  when 
  the 
  red 
  beds 
  were 
  reached. 
  

  

  1 
  Explan. 
  Sheets 
  167, 
  168, 
  etc. 
  p. 
  82. 
  

   Q. 
  J. 
  G. 
  S. 
  No. 
  210. 
  v 
  

  

  