﻿232 
  REV. 
  J. 
  F. 
  BLAKE 
  ON 
  SOME 
  [May 
  1 
  897, 
  

  

  In 
  the 
  first 
  two 
  localities 
  the 
  stratification 
  in 
  alternate 
  boulder- 
  

   and 
  non-boulder-bearing 
  beds 
  may 
  be 
  without 
  discussion 
  assigned 
  

   to 
  the 
  action 
  of 
  the 
  streams 
  when 
  they 
  were 
  depositing 
  and 
  not 
  

   eroding, 
  but 
  in 
  all 
  three 
  cases 
  the 
  difficulty 
  is 
  to 
  account 
  for 
  the 
  

   carriage 
  of 
  the 
  large 
  stones 
  and 
  their 
  promiscuous 
  heaping 
  together. 
  

   The 
  principal 
  agents 
  that 
  have 
  been 
  supposed 
  to 
  possess 
  sufficient 
  

   transporting 
  power 
  are 
  ice, 
  torrents, 
  and 
  sea-waves. 
  In 
  a 
  place 
  

   where 
  the 
  present 
  range 
  of 
  temperature 
  is 
  between 
  70° 
  and 
  120°, 
  it 
  

   is 
  scarcely 
  feasible 
  to 
  call 
  in 
  the 
  aid 
  of 
  ice, 
  and 
  certainly 
  sea-waves 
  

   are 
  out 
  of 
  the 
  question. 
  In 
  the 
  first 
  two 
  localities, 
  where 
  the 
  

   boulder-beds 
  fill 
  up 
  the 
  bottom 
  of 
  valleys 
  at 
  the 
  end 
  of 
  gorges 
  

   leading 
  out 
  from 
  lofty 
  domes, 
  the 
  bottom 
  beds 
  may 
  be 
  fairly 
  

   ascribed 
  to 
  the 
  force 
  of 
  the 
  water, 
  with 
  or 
  without 
  further 
  aid 
  ; 
  but 
  

   those 
  which 
  overlie 
  the 
  soft 
  concrete 
  could 
  scarcely, 
  one 
  would 
  

   think, 
  be 
  borne 
  along 
  in 
  so 
  rapid 
  a 
  torrent 
  that 
  they 
  could 
  not 
  

   even 
  be 
  sorted, 
  without 
  that 
  torrent 
  eroding 
  the 
  surface 
  below. 
  

  

  Eor 
  the 
  third 
  locality, 
  however, 
  there 
  seems 
  no 
  possibility 
  of 
  calling 
  

   in 
  the 
  aid 
  of 
  a 
  torrent, 
  as 
  there 
  is 
  no 
  gathering-ground 
  for 
  the 
  water. 
  

   The 
  whole 
  history 
  of 
  the 
  deposit 
  must 
  at 
  the 
  outside 
  be 
  confined 
  

   within 
  an 
  area 
  of 
  1| 
  square 
  miles 
  on 
  which 
  no 
  longer 
  line 
  than 
  

   2k 
  miles 
  can 
  be 
  drawn, 
  with 
  a 
  maximum 
  difference 
  of 
  elevation 
  of 
  

   1150 
  feet. 
  But 
  the 
  mounds 
  point 
  in 
  the 
  direction 
  of 
  the 
  scarp 
  

   only 
  1^ 
  miles 
  distant 
  and 
  whose 
  highest 
  point 
  is 
  only 
  640 
  feet 
  

   abo\ 
  r 
  e 
  their 
  surface, 
  and 
  for 
  three-quarters 
  of 
  this 
  distance 
  the 
  

   boulders 
  occur. 
  Nor 
  do 
  they 
  fill 
  up 
  a 
  valley, 
  but 
  form 
  mounds 
  on 
  a 
  

   flat 
  surface. 
  The 
  only 
  area 
  whence 
  the 
  water 
  could 
  be 
  obtained 
  to 
  

   form 
  a 
  torrent 
  would 
  thus 
  be 
  the 
  slopes 
  of 
  the 
  hills 
  opposite 
  the 
  

   mounds, 
  with 
  an 
  average 
  fall 
  of 
  only 
  320 
  feet. 
  This 
  appears 
  to 
  

   me 
  quite 
  inadequate 
  to 
  produce 
  a 
  torrent 
  sufficient 
  to 
  carry 
  large 
  

   stones 
  over 
  a 
  nearly 
  level 
  surface 
  for 
  -fa 
  mile. 
  If 
  we 
  take 
  the 
  

   longer 
  oblique 
  line 
  and 
  greater 
  height 
  the 
  difficulty 
  is 
  found 
  to 
  be 
  

   not 
  lessened 
  but 
  increased. 
  

  

  In 
  the 
  29th 
  volume 
  (1873) 
  of 
  the 
  Journal 
  of 
  this 
  Society, 
  p. 
  493, 
  

   Dr. 
  W. 
  T. 
  Blanford 
  describes 
  similar 
  deposits 
  on 
  a 
  far 
  larger 
  scale 
  

   in 
  Persia. 
  Here 
  there 
  are 
  boulder-ridges 
  extending 
  for 
  5 
  to 
  10 
  

   miles 
  from 
  the 
  foot 
  of 
  the 
  hills, 
  with 
  a 
  fall 
  of 
  their 
  upper 
  surface 
  in 
  

   that 
  distance 
  of 
  1000 
  to 
  2000 
  feet. 
  He 
  says 
  that 
  the 
  large 
  fragments 
  

   are 
  commonest 
  near 
  places 
  where 
  small 
  streams 
  issue 
  from 
  the 
  

   higher 
  ranges, 
  but 
  the 
  mounds 
  increase 
  in 
  quantity 
  towards 
  the 
  north 
  

   and 
  east, 
  where 
  the 
  rainfall 
  is 
  less. 
  I 
  thought 
  that 
  this 
  last 
  fact 
  would 
  

   have 
  led 
  the 
  author 
  to 
  enunciate 
  the 
  theory 
  which 
  I 
  am 
  about 
  to 
  

   expound, 
  but 
  he 
  argues 
  only 
  that 
  there 
  must 
  have 
  been 
  a 
  greater 
  

   rainfall 
  in 
  past 
  times, 
  and 
  that 
  lakes 
  were 
  thus 
  produced 
  — 
  without 
  

   saying 
  how 
  even 
  then 
  these 
  boulders 
  could 
  have 
  been 
  transported 
  for 
  

   5 
  to 
  10 
  miles 
  with 
  so 
  little 
  fall. 
  

  

  In 
  Cutch 
  these 
  boulder-beds 
  occur 
  only 
  where 
  there 
  are 
  deposits 
  

   of 
  seolian 
  origin, 
  and 
  in 
  Persia 
  they 
  are 
  most 
  abundant 
  where 
  there 
  

   is 
  less 
  rain 
  and 
  therefore 
  presumably 
  more 
  dry 
  sand 
  to 
  be 
  blown 
  

   about, 
  so 
  that 
  some 
  connexion 
  between 
  the 
  two 
  is 
  suggested. 
  It 
  

   appears 
  to 
  me 
  that, 
  if 
  we 
  suppose 
  that 
  at 
  one 
  time 
  there 
  was 
  more 
  

  

  