﻿Vol. 
  53-] 
  GLACIO-MARINE 
  DRIFT 
  OF 
  THE 
  YALE 
  OF 
  CLWYD. 
  

  

  345 
  

  

  St. 
  Asaph 
  road, 
  north-west 
  of 
  Parc-y-Meirch, 
  220 
  feet 
  above 
  O.D., 
  a 
  

   stream 
  has 
  cut 
  into 
  the 
  drift, 
  over 
  which 
  it 
  falls 
  for 
  a 
  few 
  feet 
  as 
  

   a 
  waterfall, 
  and 
  here 
  is 
  disclosed 
  a 
  well-stratified 
  sandy 
  deposit. 
  

  

  My 
  observations 
  generally 
  go 
  to 
  show 
  that 
  the 
  drift 
  here 
  described 
  

   represents 
  a 
  shore 
  sloping 
  up 
  gradually 
  from 
  the 
  lowland 
  of 
  the 
  Vale 
  

   of 
  Clwyd, 
  until 
  it 
  is 
  backed 
  up 
  at 
  a 
  greater 
  angle 
  against 
  the 
  lime- 
  

   stone-cliffs 
  forming 
  the 
  west 
  side 
  of 
  the 
  Vale. 
  

  

  (2) 
  Glacial 
  Sands 
  and 
  Gravels, 
  east 
  side 
  of 
  the 
  

   Vale 
  of 
  Clwyd. 
  

  

  The 
  country 
  between 
  Rhyddlan 
  and 
  Diserth 
  is 
  mostly 
  covered 
  

   with 
  red 
  sand, 
  evidently 
  derived 
  from 
  the 
  Trias, 
  which 
  is 
  the 
  bottom 
  

   rock 
  of 
  the 
  Vale. 
  1 
  

  

  South-east 
  of 
  Diserth 
  Castle, 
  near 
  Prestatyn 
  Branch 
  Eailway, 
  is 
  a 
  

   striking 
  grass-covered 
  mound 
  of 
  sand 
  and 
  gravel 
  (No. 
  5 
  in 
  the 
  Map),' 
  2 
  

  

  W 
  

  

  Esker 
  south-east 
  of 
  Diserth 
  Castle. 
  

   A 
  

  

  I 
  bou 
  

   bro^ 
  

  

  Large 
  Limestone 
  -Boulders 
  

  

  the 
  structure 
  of 
  which 
  may 
  be 
  investigated 
  where 
  it 
  is 
  broken 
  into 
  

   by 
  the 
  excavations 
  for 
  gravel. 
  The 
  axis 
  of 
  this 
  mound 
  has 
  a 
  

   north-easterly 
  trend, 
  and 
  it 
  forms 
  a 
  spur 
  from 
  the 
  hill 
  on 
  which 
  it 
  

   lies. 
  Orographically 
  it 
  resembles 
  an 
  Irish 
  esker. 
  The 
  excavation 
  

   shows 
  that 
  the 
  bedding 
  of 
  the 
  sand 
  and 
  gravel 
  largely 
  follows 
  the 
  

   external 
  form, 
  the 
  flank, 
  where 
  exposed, 
  being 
  covered 
  with 
  a 
  

   layer 
  of 
  Boulder 
  Clay, 
  as 
  illustrated 
  in 
  the 
  above 
  diagram. 
  In 
  the 
  

  

  1 
  Between 
  Abergele 
  and 
  Rhyddlan 
  the 
  Glacial 
  beds 
  are 
  masked 
  by 
  post- 
  

   Glacial 
  deposits, 
  but 
  borings 
  seem 
  to 
  show 
  that 
  Boulder 
  Clay 
  and 
  Sands 
  alternate. 
  

   There 
  are 
  good 
  sections 
  of 
  the 
  Marine 
  Drift 
  on 
  the 
  river-bank 
  at 
  R-hyddlan, 
  and 
  

   these 
  have 
  been 
  described 
  by 
  Prof. 
  M 
  C 
  K. 
  Hughes, 
  ' 
  Geol. 
  of 
  the 
  Vale 
  of 
  Clwyd,' 
  

   Proc. 
  Chester 
  Soc. 
  Nat. 
  Sci. 
  1884, 
  no. 
  3. 
  See 
  also 
  remarks 
  on 
  Drift 
  in 
  ' 
  Trias 
  of 
  

   the 
  Yale 
  of 
  Clwyd,' 
  Proc. 
  Liverp. 
  Geol. 
  Soc, 
  Session 
  1890-91, 
  vol. 
  vi.pt. 
  iii.p. 
  285. 
  

  

  2 
  See 
  ' 
  Geology 
  of 
  Rhyl, 
  Abergele, 
  and 
  Colwyn 
  ' 
  (p. 
  32 
  & 
  map), 
  by 
  Aubrey 
  

   Strahan, 
  Mem. 
  Geol. 
  Surv. 
  

  

  