﻿1863.] 
  

  

  ADAMS 
  NILE 
  VALLEY. 
  

  

  D 
  

  

  the 
  soil 
  has 
  been 
  undisturbed 
  and 
  exposed 
  to 
  the 
  action 
  of 
  the 
  atmo- 
  

   sphere 
  for 
  a 
  length 
  of 
  time. 
  The 
  formation 
  is 
  going 
  on 
  at 
  present, 
  

   and 
  is 
  caused, 
  no 
  doubt, 
  by 
  some 
  affinity 
  between 
  the 
  air 
  and 
  the 
  

   chemical 
  components 
  of 
  the 
  river- 
  alluvium. 
  When 
  met 
  with 
  on 
  

   the 
  sands 
  of 
  the 
  desert, 
  it 
  indicates 
  an 
  alluvial 
  deposit 
  underneath. 
  

   Among 
  the 
  ancient 
  river- 
  deposits 
  on 
  the 
  plain 
  eastward 
  of 
  Wadi 
  

   Halfeh, 
  at 
  the 
  foot 
  of 
  the 
  Second 
  Cataract, 
  this 
  substance 
  abounds, 
  

   either 
  in 
  the 
  shape 
  of 
  nodular 
  fragments 
  * 
  on 
  the 
  surface, 
  or 
  in 
  masses 
  

   mingled 
  with 
  the 
  soil. 
  It 
  has 
  a 
  great 
  resemblance 
  to 
  the 
  Kunkar 
  of 
  

   India, 
  with 
  which 
  it 
  appears 
  to 
  me 
  almost, 
  if 
  not 
  absolutely, 
  iden- 
  

   tical 
  f 
  . 
  

  

  3. 
  Terraces 
  of 
  the 
  Valley 
  ; 
  their 
  Cliffs 
  and 
  Caves. 
  — 
  Taking 
  a 
  gene- 
  

   ral 
  view 
  of 
  the 
  Nile 
  Valley 
  between 
  the 
  First 
  and 
  Second 
  Cataracts, 
  

   one 
  is 
  struck 
  with 
  the 
  regularity 
  with 
  which 
  terrace-cliffs 
  and 
  flats 
  

   continue 
  ; 
  indeed, 
  except 
  at 
  broken 
  intervals, 
  these 
  appearances 
  are 
  

   pretty 
  clearly 
  denned 
  even 
  as 
  far 
  down 
  as 
  Selsileh, 
  about 
  36 
  miles 
  

   below 
  the 
  First 
  Cataract. 
  At 
  first 
  there 
  may 
  be 
  some 
  difficulty 
  in 
  

   tracing 
  these 
  levels, 
  but 
  after 
  a 
  little 
  experience 
  their 
  presence 
  be- 
  

   comes 
  evident 
  ; 
  and, 
  except 
  where 
  the 
  soil 
  has 
  been 
  removed 
  by 
  the 
  

   action 
  of 
  rain, 
  <fcc, 
  I 
  had 
  no 
  difficulty 
  in 
  finding 
  abundance 
  of 
  river- 
  

   shells 
  at 
  altitudes 
  of 
  at 
  least 
  120 
  feet 
  above 
  the 
  highest 
  Nile 
  of 
  the 
  

   present 
  time. 
  

  

  The 
  junction 
  between 
  the 
  sandstone 
  and 
  granitic 
  rocks 
  is 
  not 
  

   always 
  observed 
  to 
  be 
  even 
  or 
  regular, 
  as 
  we 
  find 
  the 
  latter 
  often, 
  

   as 
  it 
  were, 
  dovetailing 
  into 
  the 
  sandstone 
  above, 
  as 
  here 
  represented 
  

  

  (%. 
  I)- 
  

  

  Fig. 
  1. 
  — 
  Diagram 
  showing 
  the 
  Line 
  of 
  Junction 
  of 
  the 
  Granite 
  and 
  

  

  Sandstone 
  in 
  Nubia. 
  

  

  Sandstone. 
  

  

  "•• 
  » 
  o 
  o 
  

  

  Granite. 
  

  

  In 
  this 
  way 
  Ave 
  can 
  suppose 
  the 
  insular 
  prominences 
  of 
  the 
  Cata- 
  

   racts 
  to 
  have 
  been 
  caused 
  by 
  the 
  softer 
  sandstone 
  being 
  washed 
  

   away. 
  

  

  The 
  point 
  of 
  junction 
  between 
  the 
  two 
  rocks 
  is 
  often 
  marked 
  by 
  

   layers 
  of 
  rounded 
  water-worn 
  pebbles, 
  or 
  coarse 
  gravelly 
  sand, 
  

   which, 
  however, 
  may 
  be 
  frequently 
  seen 
  running 
  in 
  veins 
  throughout 
  

  

  * 
  See 
  Specimen 
  No. 
  6. 
  

  

  t 
  Veins 
  of 
  oxide 
  of 
  iron 
  are 
  common 
  between 
  Thebes 
  and 
  Gofu, 
  and 
  are 
  best 
  

   seen 
  on 
  the 
  face 
  of 
  the 
  recent 
  alluvial 
  banks, 
  where 
  they 
  run 
  horizontally 
  for 
  

   several 
  miles 
  in 
  the 
  form 
  of 
  reddish 
  bands. 
  

  

  