﻿1864.] 
  MAW 
  BOULDER-CLAY. 
  445 
  

  

  foot 
  per 
  second) 
  rose 
  about 
  1 
  foot 
  above 
  the 
  surface, 
  coming 
  from 
  a 
  

   depth 
  of 
  525 
  English 
  feet 
  ; 
  its 
  temperature 
  was 
  52° 
  Fahr. 
  

   The 
  following 
  beds 
  were 
  passed 
  through 
  : 
  — 
  

  

  feet. 
  

  

  1. 
  Alluvium 
  and 
  diluvium 
  (at 
  the 
  depth 
  of 
  80 
  feet 
  excellent 
  1 
  Rft 
  

  

  water 
  rose 
  2 
  feet 
  above 
  the 
  surface) 
  J 
  

  

  2. 
  Greenish 
  clay 
  (Silurian), 
  with 
  Fucus 
  300 
  

  

  3. 
  Fine-grained 
  sandstone, 
  very 
  hard, 
  with 
  some 
  alternations 
  1 
  .. 
  Q 
  „ 
  

  

  of 
  clay 
  J 
  ld/ 
  

  

  525 
  

  

  At 
  the 
  depth 
  of 
  414 
  feet 
  a 
  second 
  issue 
  of 
  water 
  was 
  met 
  with 
  ; 
  

   it 
  was 
  slightly 
  salt, 
  and 
  more 
  abundant 
  than 
  the 
  first. 
  The 
  third 
  

   discharge 
  of 
  water, 
  which 
  rose 
  with 
  great 
  force, 
  was 
  reached 
  at 
  the 
  

   depth 
  of 
  517 
  feet. 
  Its 
  quantity 
  and 
  height 
  were 
  augmented 
  when 
  

   they 
  bored 
  6 
  feet 
  deeper. 
  This 
  water 
  proceeds 
  from 
  a 
  bed 
  of 
  gravel, 
  

   which 
  is 
  the 
  result 
  of 
  degradation 
  of 
  Finland 
  Granite. 
  It 
  was 
  pro- 
  

   posed 
  to 
  bore 
  down 
  to 
  the 
  Granite 
  in 
  situ, 
  which, 
  as 
  Professor 
  Hel- 
  

   mersen 
  believed, 
  would 
  very 
  soon 
  be 
  reached. 
  This 
  would 
  be 
  an 
  

   interesting 
  geological 
  fact. 
  

  

  5. 
  On 
  a 
  Supposed 
  Deposit 
  of 
  Boulder-Clay 
  in 
  North 
  Devon. 
  

   By 
  George 
  Maw, 
  Esq., 
  F.G.S., 
  F.S.A., 
  F.L.S. 
  

  

  [Abridged.] 
  

  

  A 
  deposit 
  of 
  brown 
  potter's 
  clay, 
  of 
  rather 
  a 
  peculiar 
  character, 
  has 
  

   for 
  many 
  years 
  been 
  worked 
  near 
  Fremington, 
  a 
  village 
  three 
  miles 
  

   to 
  the 
  south-west 
  of 
  Barnstaple; 
  and 
  lately, 
  by 
  the 
  sinking 
  of 
  a 
  well 
  

   to 
  the 
  east 
  of 
  Fremington, 
  a 
  much 
  greater 
  thickness 
  and 
  extent 
  of 
  

   the 
  deposit 
  have 
  been 
  ascertained 
  than 
  was 
  evident 
  when 
  I 
  first 
  mea- 
  

   sured 
  and 
  inspected 
  the 
  sections 
  that 
  were 
  exposed, 
  in 
  1852, 
  in 
  the 
  

   open 
  clay-pits. 
  

  

  To 
  the 
  south-west 
  of 
  Barnstaple, 
  on 
  the 
  south 
  side 
  of 
  the 
  valley 
  

   of 
  the 
  Taw, 
  extends 
  a 
  low 
  range 
  of 
  rounded 
  hills 
  of 
  Carboniferous 
  

   and 
  Devonian 
  shales, 
  beyond 
  which, 
  connecting 
  the 
  valley 
  of 
  the 
  

   Taw 
  (which 
  here 
  forms 
  a 
  loop 
  to 
  the 
  northward) 
  in 
  a 
  more 
  direct 
  

   line 
  from 
  the 
  river 
  above 
  to 
  the 
  river 
  below 
  Barnstaple, 
  is 
  another 
  

   valley 
  at 
  a 
  higher 
  level, 
  the 
  site 
  of 
  the 
  deposit 
  about 
  to 
  be 
  de- 
  

   scribed. 
  

  

  Its 
  base, 
  as 
  far 
  as 
  I 
  have 
  been 
  able 
  to 
  ascertain, 
  consists 
  through- 
  

   out 
  of 
  a 
  bed 
  of 
  shingly 
  gravel, 
  the 
  top 
  of 
  which 
  is 
  about 
  35 
  feet 
  

   above 
  high-water 
  mark. 
  In 
  appearance 
  it 
  closely 
  resembles 
  the 
  

   coarser 
  beds 
  of 
  the 
  Severn 
  Valley 
  Drifts, 
  excepting 
  that 
  it 
  is 
  for 
  the 
  

   most 
  part 
  composed 
  of 
  water- 
  worn 
  fragments 
  of 
  the 
  Carboniferous 
  

   grits 
  and 
  shales 
  of 
  Devon. 
  It 
  is 
  evidently 
  identical 
  and 
  corresponds 
  

   in 
  height 
  with 
  the 
  raised 
  beaches 
  of 
  the 
  neighbourhood 
  mentioned 
  

   by 
  De 
  la 
  Beche 
  in 
  his 
  ' 
  Geology 
  of 
  Cornwall, 
  Devon, 
  and 
  West 
  

   Somerset,' 
  though 
  he 
  makes 
  no 
  mention 
  of 
  their 
  extension 
  inland 
  for 
  

   several 
  miles, 
  nor 
  of 
  the 
  great 
  mass 
  of 
  clay 
  that 
  partly 
  overlies 
  them. 
  

  

  vol. 
  xx. 
  — 
  part 
  i. 
  2 
  I 
  

  

  