﻿694 
  SEARLES 
  T. 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  Amongst 
  the 
  Mammalia, 
  the 
  presence 
  of 
  the 
  Fallow 
  Deer 
  and 
  the 
  

   absence 
  of 
  the 
  Reindeer 
  have 
  been 
  cited 
  as 
  evidence 
  of 
  mild 
  climate, 
  

   and 
  the 
  presence 
  of 
  Rhinoceros 
  megarhinus 
  as 
  evidence 
  of 
  perhaps 
  

   the 
  same 
  kind 
  ; 
  but 
  more 
  certainly 
  (notwithstanding 
  the 
  alleged 
  

   occnrrence 
  of 
  the 
  frozen 
  carcase 
  of 
  this 
  species 
  in 
  Siberia) 
  of 
  an 
  

   antiquity 
  greater 
  than 
  the 
  cave-deposits. 
  Among 
  the 
  Molluscan 
  

   remains 
  evidence 
  more 
  decisive 
  is 
  found 
  ; 
  for 
  of 
  the 
  three 
  freshwater 
  

   shells 
  of 
  this 
  formation, 
  one, 
  Cyrena 
  fluminalis, 
  is 
  not 
  known 
  living 
  

   nearer 
  to 
  us 
  than 
  the 
  Nile, 
  and 
  inhabits 
  the 
  rivers 
  of 
  Thibet 
  and 
  China, 
  

   and 
  two 
  others, 
  Uniolittoralis 
  and 
  Hydrobia 
  marginata, 
  are 
  not 
  known 
  

   living 
  nearer 
  to 
  us 
  than 
  the 
  South 
  of 
  Prance. 
  The 
  Musk-Ox 
  cranium 
  

   (which, 
  judging 
  from 
  Prof. 
  Dawkins's 
  figure, 
  seems 
  to 
  have 
  occurred 
  

   at 
  Crayford 
  in 
  bed 
  No. 
  2 
  of 
  the 
  formation) 
  points 
  in 
  the 
  other 
  di- 
  

   rection 
  so 
  far 
  as 
  it 
  goes 
  ; 
  and 
  as 
  the 
  Cyrena 
  lived 
  during 
  the 
  Upper 
  

   Crag 
  (and 
  even 
  at 
  the 
  beginning 
  of 
  the 
  sand 
  b 
  i), 
  it 
  is 
  probable 
  that 
  

   the 
  climate 
  of 
  this 
  Crag 
  and 
  of 
  the 
  Cyrena- 
  formation 
  did 
  not 
  much 
  

   differ, 
  though 
  probably 
  the 
  latter 
  was 
  milder 
  than 
  the 
  former. 
  

  

  In 
  tracing 
  the 
  distribution 
  of 
  this 
  formation 
  as 
  far 
  as 
  known, 
  I 
  

   commence 
  with 
  the 
  recent 
  discovery 
  of 
  it 
  by 
  Prof. 
  Prestwich, 
  in 
  

   the 
  form 
  of 
  a 
  sand 
  at 
  Oxford, 
  from 
  20 
  to 
  2b 
  feet 
  above 
  the 
  level 
  of 
  

   the 
  Isis, 
  more 
  than 
  300 
  feet 
  below 
  that 
  of 
  the 
  gravel 
  b' 
  on 
  the 
  hills 
  

   around, 
  and 
  from 
  400 
  to 
  500 
  feet 
  below 
  the 
  line 
  of 
  maximum 
  sub- 
  

   mergence 
  there. 
  The 
  spot 
  is 
  distant 
  24 
  miles 
  from 
  the 
  water-parting 
  

   of 
  the 
  Thames 
  and 
  Severn 
  systems 
  by 
  way 
  of 
  the 
  Evenlode, 
  and 
  30 
  

   miles 
  from 
  that 
  by 
  way 
  of 
  the 
  Cherwell 
  ; 
  and 
  the 
  elevation 
  of 
  the 
  sand 
  

   yielding 
  the 
  shell 
  is 
  about 
  230 
  feet 
  below 
  the 
  elevation 
  of 
  these 
  part- 
  

   ings. 
  Prof. 
  Prestwich, 
  however, 
  mentions 
  that 
  a 
  single 
  specimen 
  

   was 
  obtained 
  years 
  ago 
  from 
  a 
  pit 
  on 
  the 
  banks 
  of 
  the 
  Cherwell, 
  and 
  

   nearer 
  therefore 
  to 
  that 
  parting. 
  The 
  occurrence 
  of 
  it 
  at 
  Erith, 
  Cray- 
  

   ford, 
  Ilford, 
  and 
  Grays 
  is 
  too 
  well 
  known 
  to 
  need 
  mention 
  ; 
  and 
  

   I 
  believe 
  that 
  it 
  has 
  occurred 
  near 
  Southend, 
  but 
  have 
  not 
  verified 
  

   such 
  occurrence. 
  Although 
  at 
  all 
  these 
  places 
  below 
  London 
  the 
  

   transgressive 
  character 
  of 
  the 
  successive 
  beds 
  of 
  the 
  formation 
  is 
  ap- 
  

   parent, 
  it 
  is 
  further 
  to 
  seaward, 
  viz. 
  at 
  Clacton 
  on 
  the 
  coast, 
  in 
  the 
  

   south 
  centre 
  of 
  Sheet 
  48, 
  that 
  we 
  find 
  the 
  first 
  distinct 
  evidence 
  of 
  

   the 
  depression 
  to 
  which 
  this 
  transgression 
  is 
  due 
  having 
  changed 
  

   the 
  fresh 
  to 
  salt 
  water. 
  At 
  that 
  place 
  the 
  freshwater 
  part 
  of 
  this 
  

   formation, 
  abounding 
  in 
  valves 
  (often 
  joined) 
  of 
  Unio 
  littoralis, 
  as- 
  

   sociated 
  only 
  with 
  other 
  shells 
  exclusively 
  of 
  freshwater 
  habit, 
  de- 
  

   scends 
  below 
  the 
  level 
  of 
  high-water 
  on 
  the 
  sea-beach 
  ; 
  but 
  upwards 
  

   in 
  the 
  Cliff 
  section, 
  this 
  part 
  changes 
  gradually 
  into 
  a 
  bed 
  containing 
  

   marine 
  shells, 
  along 
  with 
  which 
  Cyrena 
  Jluminalis 
  was 
  found 
  by 
  

   Mr. 
  O. 
  Pisher 
  (see 
  bed 
  <p 
  3 
  of 
  fig. 
  XXIV.). 
  

  

  Tn 
  section 
  8 
  of 
  the 
  plate 
  to 
  a 
  paper 
  in 
  the 
  ' 
  Geological 
  Magazine 
  ' 
  

   for 
  1866, 
  p. 
  348, 
  1 
  first 
  showed 
  the 
  position 
  of 
  the 
  Clacton 
  part 
  of 
  this 
  

   formation 
  relatively 
  to 
  the 
  gravel 
  / 
  in 
  the 
  Clacton 
  and 
  Holland 
  Cliff 
  ; 
  

   but 
  I 
  have 
  now 
  given 
  fig. 
  XXVII. 
  to 
  show 
  not 
  only 
  this, 
  but 
  also 
  

   the 
  position 
  of 
  / 
  relatively 
  to 
  the 
  gravel 
  at 
  Tolleshunt 
  ; 
  the 
  relation 
  

   of 
  which 
  again 
  is 
  in 
  fig. 
  YII. 
  (in 
  the 
  plate 
  to 
  the 
  first 
  part 
  of 
  this 
  

   memoir) 
  shown 
  relatively 
  to 
  the 
  gravels 
  c 
  and 
  b\ 
  Mr. 
  Fisher's 
  section 
  

  

  