﻿1864.] 
  MAW 
  SEVERN-VALLEY 
  DRIFT. 
  133 
  

  

  few 
  feet 
  at 
  the 
  bottom 
  of 
  the 
  railway-cutting 
  and 
  also 
  on 
  the 
  oppo- 
  

   site 
  side 
  of 
  the 
  river, 
  near 
  to 
  Buildwas 
  Station, 
  in 
  the 
  gravel-pits 
  

   which 
  supply 
  ballast 
  for 
  all 
  the 
  neighbouring 
  lines 
  of 
  railway; 
  

   and 
  the 
  continuity 
  of 
  these 
  beds 
  is 
  further 
  verified 
  by 
  the 
  section 
  at 
  

   the 
  end 
  of 
  the 
  cutting 
  next 
  Coalbrook 
  Dale, 
  where 
  these 
  fine 
  sea- 
  

   sand 
  beds 
  are 
  found 
  coming 
  up 
  under 
  the 
  other 
  beds, 
  and 
  leaning 
  

   against 
  the 
  old 
  coast 
  of 
  Wenlock 
  shale. 
  

  

  At 
  the 
  height 
  of 
  60 
  or 
  70 
  feet 
  above 
  the 
  river, 
  and 
  about 
  165 
  feet 
  

   above 
  the 
  sea, 
  these 
  clean 
  sand-beds 
  are 
  replaced 
  by 
  a 
  most 
  hetero- 
  

   geneous 
  mass 
  of 
  drift, 
  in 
  which 
  stratification 
  is 
  almost 
  absent 
  ; 
  

   they 
  are 
  about 
  60 
  feet 
  thick, 
  and 
  included 
  within 
  the 
  top 
  and 
  bot- 
  

   tom 
  of 
  the 
  railway- 
  cutting. 
  So 
  singularly 
  various 
  is 
  their 
  aspect, 
  and 
  

   so 
  obvious 
  in 
  irregularity 
  and 
  variety 
  of 
  structure 
  and 
  materials, 
  as 
  

   to 
  call 
  forth 
  the 
  remark 
  from 
  one 
  of 
  the 
  navvies 
  that 
  " 
  he 
  had 
  cut 
  

   through 
  plenty 
  of 
  hills 
  in 
  his 
  time, 
  but 
  that 
  he 
  had 
  never 
  seen 
  a 
  hill 
  

   with 
  such 
  a 
  many 
  kinds 
  of 
  muck 
  in 
  it 
  as 
  this." 
  The 
  transition 
  from 
  

   the 
  sand-beds 
  is 
  well-marked 
  and 
  sudden, 
  and 
  the 
  beds 
  immediately 
  

   succeeding 
  them 
  consist 
  of 
  muddy 
  subangular 
  gravel, 
  irregularly 
  

   stratified, 
  and 
  containing 
  beds 
  of 
  silt, 
  drift-coal, 
  and 
  clay 
  irregu- 
  

   larly 
  disposed, 
  and 
  also, 
  in 
  common 
  with 
  nearly 
  the 
  whole 
  mass 
  of 
  

   drift, 
  rocks 
  and 
  stones 
  of 
  various 
  sizes 
  and 
  from 
  many 
  formations, 
  a 
  

   list 
  of 
  which 
  is 
  given 
  below. 
  

  

  The 
  middle 
  of 
  this 
  heterogeneous 
  stratum 
  consists 
  of 
  a 
  mass 
  of 
  

   very 
  tough 
  unstratified 
  clay, 
  containing 
  fragments 
  of 
  Wenlock 
  shale, 
  

   water- 
  worn 
  and 
  subangular 
  boulders, 
  pieces 
  of 
  flint, 
  and 
  patches 
  of 
  

   curiously 
  contorted 
  sand 
  and 
  silt, 
  the 
  structure 
  of 
  which 
  is 
  very 
  

   similar 
  to 
  that 
  of 
  the 
  strata 
  at 
  St. 
  Acheul, 
  engraved 
  at 
  page 
  138 
  of 
  

   * 
  The 
  Antiquity 
  of 
  Man'; 
  they 
  seem 
  to 
  have 
  been 
  subjected 
  to 
  con- 
  

   tinual 
  moving, 
  washing, 
  and 
  changing, 
  from 
  constantly 
  varying 
  cur- 
  

   rents 
  cutting 
  fresh 
  channels 
  and 
  redepositing 
  the 
  materials. 
  

  

  The 
  tough 
  clay 
  is 
  again 
  succeeded 
  by 
  muddy 
  subangular 
  gravel, 
  

   similar 
  to 
  that 
  in 
  which 
  it 
  rests. 
  The 
  transition 
  from 
  the 
  clay 
  to 
  the 
  

   muddy 
  gravels 
  immediately 
  under 
  and 
  over 
  it 
  is 
  by 
  no 
  means 
  well- 
  

   defined 
  or 
  decided, 
  as 
  they 
  break 
  into 
  each 
  other 
  with 
  the 
  utmost 
  

   irregularity 
  ; 
  indeed 
  the 
  centre 
  of 
  the 
  mass 
  is 
  only 
  separately 
  dis- 
  

   tinguishable 
  by 
  containing 
  more 
  clay 
  and 
  less 
  gravel 
  than 
  its 
  top 
  and 
  

   bottom. 
  

  

  Leaving 
  the 
  railway-cutting 
  and 
  ascending 
  the 
  hill, 
  the 
  beds 
  which 
  

   cap 
  it 
  are 
  well 
  exposed 
  in 
  the 
  old 
  gravel-pit 
  ; 
  here 
  no 
  traces 
  of 
  mud 
  

   or 
  clay 
  occur, 
  and 
  the 
  whole 
  mass 
  of 
  60 
  feet 
  is 
  made 
  up 
  of 
  evenly 
  

   stratified, 
  well-defined 
  beds 
  of 
  clean 
  sharp 
  sand 
  and 
  shingle. 
  Their 
  

   disposition 
  is 
  perfectly 
  level, 
  and, 
  what 
  I 
  would 
  particularly 
  note, 
  

   quite 
  independent 
  of 
  the 
  rounded 
  contour 
  of 
  the 
  surface 
  of 
  the 
  hill 
  — 
  a 
  

   fact 
  which 
  I 
  find 
  holds 
  good 
  with 
  all 
  the 
  stratified 
  gravels 
  of 
  the 
  neigh- 
  

   bourhood. 
  

  

  It 
  has 
  been 
  generally 
  supposed, 
  and 
  perhaps 
  correctly, 
  that 
  the 
  

   higher 
  gravel-beds 
  on 
  the 
  flanks 
  of 
  many 
  diluvial 
  valleys 
  are 
  the 
  most 
  

   ancient 
  ; 
  but, 
  in 
  the 
  case 
  of 
  Strethill, 
  the 
  fact 
  of 
  immediate 
  superposi- 
  

   tion 
  proves 
  that 
  the 
  drift 
  occupying 
  the 
  bottom 
  of 
  the 
  Severn 
  Valley, 
  

   excepting 
  the 
  flat 
  alluvium 
  immediately 
  adjacent 
  to 
  the 
  river, 
  which 
  

   contains 
  the 
  freshwater 
  Mussel, 
  and 
  may 
  possibly 
  correspond 
  with 
  the 
  

  

  