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  53«] 
  GLACI0-3IARIXE 
  DRIFT 
  OF 
  THE 
  VALE 
  OF 
  CLWYD. 
  341 
  

  

  25. 
  The 
  Glacio-Marixe 
  Drift 
  of 
  the 
  Yale 
  of 
  Clwyd. 
  By 
  T. 
  

   Mellard 
  Reade, 
  Esq., 
  C.E., 
  F.G.S., 
  E.R.I.B.A. 
  (Read 
  

   April 
  7th, 
  1897.) 
  

  

  [Plate 
  XXV— 
  Map.] 
  

  

  In 
  a 
  paper 
  on 
  the 
  Drift 
  Deposits 
  of 
  Colwyn 
  Bay, 
  I 
  pointed 
  out 
  

   that 
  the 
  bulk 
  of 
  the 
  materials 
  of 
  the 
  sands 
  and 
  clays 
  forming 
  the 
  

   Colwyn 
  drift 
  had 
  been 
  derived 
  from 
  the 
  Vale 
  of 
  Clwyd. 
  1 
  In 
  

   January, 
  1896, 
  I 
  had 
  the 
  opportunity 
  of 
  tracing 
  the 
  deposits 
  farther 
  

   westward 
  past 
  Llandulas 
  and 
  into 
  the 
  Vale 
  itself. 
  These 
  later 
  

   observations 
  quite 
  bear 
  out 
  my 
  original 
  statement. 
  

  

  (1) 
  Boulder 
  Clay 
  from 
  Craig, 
  west 
  of 
  Llandulas, 
  to 
  the 
  

   Vale 
  of 
  Clwyd, 
  south-east 
  of 
  Abergele. 
  

  

  Immediately 
  east 
  of 
  Craig, 
  between 
  Llandulas 
  and 
  Colwyn 
  Bay 
  

   (No. 
  1 
  in 
  the 
  Map) 
  the 
  Boulder 
  Clay 
  stands 
  out 
  in 
  vertical 
  cliffs 
  

   about 
  30 
  feet 
  high, 
  and 
  so 
  compact 
  that 
  it 
  is 
  undercut 
  by 
  the 
  

   waves, 
  in 
  a 
  manner 
  similar 
  to 
  that 
  often 
  seen 
  in 
  rock-cliffs. 
  A 
  

   closer 
  examination 
  shows 
  that 
  it 
  is 
  very 
  full 
  of 
  angular 
  fragments 
  of 
  

   limestone, 
  derived 
  from 
  the 
  Carboniferous 
  Limestone-rock 
  against 
  

   which 
  it 
  lies. 
  Several 
  large 
  blocks 
  of 
  Welsh 
  felstone 
  and 
  blocks 
  of 
  

   slate-rock 
  — 
  showing 
  banding 
  or 
  original 
  bedding 
  — 
  occur 
  on 
  the 
  

   shore, 
  and 
  I 
  found 
  a 
  small 
  boulder 
  of 
  Eskdale 
  granite 
  in 
  the 
  clay. 
  

   At 
  one 
  place 
  the 
  clay 
  appears 
  to 
  be 
  foliated 
  in 
  a 
  vertical 
  direction. 
  

   It 
  does 
  not 
  appear 
  that 
  there 
  are 
  many 
  shell-fragments 
  in 
  the 
  clay, 
  

   as 
  I 
  found 
  only 
  one 
  example. 
  All 
  the 
  Boulder 
  Clay 
  described 
  in 
  

   this 
  paper 
  is 
  of 
  a 
  brown 
  or 
  reddish-brown 
  colour, 
  containing 
  

   northern 
  erratics, 
  and 
  is 
  similar 
  to 
  the 
  low-level 
  Boulder 
  Clays 
  of 
  

   Lancashire 
  and 
  Cheshire, 
  excepting 
  where 
  it 
  is 
  mixed 
  with 
  the 
  

   waste 
  of 
  the 
  hills 
  against 
  which 
  it 
  may 
  happen 
  to 
  lie. 
  

  

  A 
  microscopic 
  examination 
  of 
  a 
  specimen 
  of 
  the 
  clay 
  by 
  Mr. 
  

   Joseph 
  Wright, 
  E.G.S., 
  for 
  foraminifera 
  yielded 
  negative 
  results. 
  

  

  The 
  following 
  is 
  a 
  mechanical 
  analysis 
  showing 
  the 
  constitution 
  

   of 
  the 
  clay 
  ; 
  specimen 
  taken 
  about 
  5 
  feet 
  above 
  the 
  shore 
  : 
  — 
  

  

  Weight 
  before 
  washing 
  = 
  1-000 
  = 
  5 
  oz. 
  

  

  Caught 
  in 
  ^Vhjcn 
  mesh 
  0191 
  

  

  is 
  „ 
  0033 
  

  

  t£o 
  „ 
  0-075 
  

  

  Passed 
  do. 
  & 
  deposited 
  by 
  subsidence 
  0*208 
  

  

  0-507 
  

  

  This 
  leaves 
  50 
  per 
  cent, 
  of 
  clay, 
  if 
  we 
  count 
  as 
  clay 
  all 
  the 
  material 
  

   washed 
  out 
  in 
  the 
  operations. 
  

  

  1 
  Quart. 
  Joum. 
  Geol. 
  Soc. 
  vol. 
  xli. 
  (1885) 
  pp. 
  102-107. 
  

  

  