﻿404 
  MESSES. 
  A. 
  J. 
  JTKES-BEOWXE 
  AXD 
  W. 
  HILL 
  OX 
  COLLOID 
  

  

  The 
  dip 
  is 
  southerly 
  at 
  a 
  low 
  angle, 
  except 
  at 
  one 
  place 
  where 
  

   there 
  is 
  a 
  steeper 
  inclination 
  of 
  4 
  or 
  5 
  degrees 
  for 
  a 
  short 
  distance. 
  

  

  In 
  the 
  next 
  cutting 
  to 
  the 
  north 
  two 
  hard 
  beds 
  occur 
  near 
  the 
  

   top, 
  which 
  may 
  be 
  the 
  two 
  lowermost 
  seen 
  in 
  the 
  former 
  cutting, 
  

   and 
  they 
  are 
  underlain 
  by 
  about 
  20 
  feet 
  of 
  firm 
  blocky 
  chalk, 
  with 
  

   the 
  fossils 
  of 
  the 
  Chalk 
  Marl. 
  Ammonites 
  varians 
  is 
  common 
  

   throughout, 
  and 
  the 
  following 
  are 
  not 
  uncommon 
  : 
  — 
  Amm. 
  JIcui- 
  

   telli, 
  Turrilites 
  ScheucJizerianus, 
  Inoceramus 
  latus, 
  and 
  Bhynchonella 
  

   Grasiana. 
  

  

  All 
  the 
  courses 
  described 
  as 
  " 
  hard 
  chalk 
  " 
  in 
  the 
  above 
  sections 
  

   are 
  decidedly 
  hard 
  and 
  weather 
  out 
  as 
  conspicuous 
  bands 
  along 
  the 
  

   face 
  of 
  the 
  cuttings 
  ; 
  the 
  highest 
  course, 
  however, 
  is 
  harder 
  than 
  the 
  

   others, 
  it 
  rings 
  under 
  the 
  hammer 
  and 
  only 
  breaks 
  under 
  a 
  blow 
  of 
  

   considerable 
  force. 
  The 
  broken 
  surfaces 
  of 
  the 
  hard 
  beds 
  exhibit 
  

   sparkling 
  particles, 
  some 
  of 
  which 
  may 
  be 
  small 
  flakes 
  of 
  mica, 
  but 
  

   other 
  more 
  minute 
  points 
  are 
  possibly 
  the 
  broken 
  ends 
  of 
  sponge- 
  

   spicules. 
  Recognizable 
  sponge-remains 
  are 
  common 
  throughout 
  the 
  

   whole 
  set 
  of 
  beds, 
  but 
  seldom 
  in 
  a 
  condition 
  that 
  allows 
  of 
  specific 
  

   determination. 
  

  

  Similar 
  courses 
  of 
  hard 
  chalk, 
  probably 
  in 
  all 
  cases 
  siliceous, 
  

   occur 
  in 
  the 
  same 
  stratigraphical 
  position 
  throughout 
  the 
  range 
  of 
  

   the 
  Berkshire 
  outcrop. 
  They 
  may 
  be 
  seen 
  in 
  the 
  cutting 
  on 
  the 
  

   Great 
  Western 
  Railway 
  at 
  Moulsford 
  Station, 
  in 
  a 
  deep 
  lane 
  near 
  

   East 
  Ginge, 
  above 
  Wantage, 
  and 
  in 
  road-cuttings 
  at 
  Letcombe 
  Bassett. 
  

  

  In 
  the 
  neighbourhood 
  of 
  Calne 
  and 
  Devizes 
  (Wilts) 
  the 
  Lower 
  

   Chalk 
  also 
  contains 
  beds 
  of 
  similar 
  composition. 
  This 
  division 
  of 
  

   the 
  Chalk 
  is 
  here 
  unusually 
  thick 
  (up 
  to 
  240 
  feet), 
  and 
  contains 
  

   many 
  hard 
  rocky 
  beds, 
  especially 
  in 
  the 
  upper 
  part 
  ; 
  but 
  nothing 
  

   exactly 
  like 
  the 
  Totternhoe 
  Stone 
  has 
  yet 
  been 
  discovered, 
  so 
  that 
  

   we 
  cannot 
  say 
  how 
  much 
  of 
  this 
  Chalk 
  is 
  the 
  equivalent 
  of 
  the 
  

   Chalk 
  Marl. 
  There 
  are 
  no 
  large 
  quarries 
  in 
  this 
  part 
  of 
  the 
  Chalk, 
  

   and 
  the 
  most 
  continuous 
  exposures 
  are 
  along 
  the 
  bye-roads, 
  which 
  

   have 
  been 
  cut 
  more 
  or 
  less 
  into 
  the 
  rock 
  along 
  the 
  hill-slopes, 
  the 
  

   harder 
  beds 
  often 
  making 
  a 
  succession 
  of 
  small 
  steps 
  or 
  ridges 
  across 
  

   such 
  roads. 
  

  

  The 
  hardest 
  and 
  most 
  definite 
  rock-beds 
  occur 
  in 
  the 
  upper 
  half 
  

   of 
  the 
  Lower 
  Chalk, 
  but 
  none 
  of 
  these 
  are 
  highly 
  siliceous 
  ; 
  of 
  soft 
  

   Chalk 
  Marl 
  there 
  is 
  very 
  little 
  in 
  Wiltshire, 
  not 
  more 
  than 
  10 
  feet 
  at 
  

   the 
  base, 
  all 
  the 
  rock 
  above 
  this 
  being 
  of 
  a 
  firm 
  and 
  bedded 
  or 
  

   blocky 
  nature, 
  while 
  certain 
  portions 
  of 
  it, 
  hardly 
  distinguishable 
  

   from 
  the 
  rest 
  in 
  general 
  appearance, 
  are 
  highly 
  charged 
  with 
  silica. 
  

  

  A 
  good 
  section 
  of 
  the 
  lowest 
  beds 
  may 
  be 
  found 
  to 
  the 
  east 
  of 
  

   Compton 
  Bassett, 
  near 
  Calne, 
  where 
  a 
  pit 
  and 
  a 
  road-cutting 
  show 
  

   about 
  50 
  feet 
  of 
  the 
  firm 
  chalk 
  resting 
  upon 
  10 
  feet 
  of 
  soft 
  Chalk 
  

   Marl. 
  Several 
  beds 
  harder 
  than 
  the 
  rest 
  stand 
  out 
  in 
  the 
  road- 
  

   cutting 
  and 
  are 
  more 
  or 
  less 
  siliceous. 
  

  

  Silica, 
  however, 
  appears 
  to 
  be 
  most 
  abundant 
  in 
  the 
  central 
  part 
  

   of 
  the 
  Lower 
  Chalk 
  from 
  100 
  to 
  ] 
  20 
  feet 
  above 
  the 
  base. 
  On 
  Etchil- 
  

   hampton 
  Hill, 
  east 
  of 
  Devizes, 
  there 
  is 
  a 
  small 
  pit 
  about 
  100 
  feet 
  

   above 
  the 
  base-line, 
  which 
  exposes 
  flaggy 
  greyish-white 
  chalk 
  (o 
  feet) 
  

  

  