﻿1863.} 
  ADAMS 
  — 
  NILE 
  VALLEY. 
  17 
  

  

  ing 
  a 
  perpendicular 
  section 
  of 
  stratified 
  mud, 
  which 
  I 
  ascertained 
  

   by 
  measurement 
  to 
  average 
  between 
  80 
  and 
  90 
  feet 
  in 
  height*. 
  The 
  

   lines 
  of 
  bedding 
  are 
  not 
  always 
  parallel, 
  but, 
  as 
  the 
  accompanying 
  

   sketch 
  (fig. 
  4) 
  shows, 
  are 
  also 
  oblique, 
  which 
  I 
  conceive 
  might 
  

   result 
  from 
  the 
  mud 
  having 
  been 
  deposited 
  by 
  eddies 
  and 
  swirls. 
  

  

  Fig. 
  4. 
  — 
  Diagram-section 
  of 
  an 
  Alluvial 
  Bank 
  at 
  Maneehe, 
  

  

  below 
  Ombos. 
  

  

  The 
  surface 
  is, 
  as 
  usual, 
  covered 
  with 
  drifted 
  sand 
  and 
  pebbles. 
  I 
  

   found 
  no 
  organic 
  remains 
  in 
  this 
  bed 
  ; 
  but 
  my 
  examination 
  was 
  not 
  

   sufficiently 
  extensive 
  to 
  enable 
  me 
  to 
  speak 
  confidently 
  on 
  that 
  

   point. 
  

  

  Besides 
  the 
  above, 
  I 
  noticed, 
  for 
  the 
  first 
  and 
  last 
  time, 
  on 
  its 
  

   southern 
  flank, 
  a 
  great 
  bed 
  of 
  stratified 
  sand, 
  red 
  and 
  variegated 
  ; 
  

   throughout 
  were 
  interspersed 
  rounded 
  and 
  oval 
  masses 
  t 
  of 
  sandstone, 
  

   of 
  a 
  black 
  colour 
  externally, 
  becoming 
  paler 
  towards 
  their 
  centres, 
  

   and 
  varying 
  in 
  size 
  from 
  small 
  oblong 
  sticks 
  to 
  flat 
  oval-shaped 
  

   lumps 
  several 
  feet 
  in 
  length. 
  In 
  consistence 
  this 
  sand-bank 
  ap- 
  

   peared 
  firm 
  and 
  indurated. 
  Again, 
  on 
  the 
  opposite 
  bank, 
  a 
  mile 
  

   below 
  Ombos, 
  we 
  noticed 
  quantities 
  of 
  a 
  white 
  substance 
  +, 
  in 
  the 
  

   shape 
  of 
  roots 
  of 
  trees, 
  interspersed 
  throughout 
  the 
  alluvial 
  deposit. 
  

  

  The 
  before-mentioned 
  old 
  mud-beds 
  are 
  in 
  all 
  probability 
  the 
  de- 
  

   posit 
  of 
  the 
  river 
  ; 
  but 
  the 
  variegated 
  red 
  sand 
  and 
  its 
  nodules 
  are 
  

   very 
  different 
  from 
  any 
  formation 
  that 
  I 
  have 
  seen 
  in 
  the 
  Valley 
  of 
  

   the 
  Nile. 
  From 
  the 
  general 
  appearance 
  of 
  the 
  surrounding 
  country, 
  

   it 
  seemed 
  to 
  me 
  an 
  excellent 
  locality 
  for 
  studying 
  the 
  earlier 
  de- 
  

   posits 
  of 
  the 
  river. 
  No 
  doubt 
  between 
  Assuan 
  and 
  Selsileh, 
  where 
  

   the 
  country 
  opens 
  out, 
  the 
  early 
  Nile 
  had 
  time 
  to 
  deposit 
  the 
  debris 
  

   which 
  it 
  could 
  not 
  lay 
  down 
  in 
  its 
  narrow 
  mountain- 
  course 
  above 
  

   the 
  First 
  Cataract. 
  

  

  11. 
  Selsileh 
  and 
  vicinity. 
  — 
  The 
  white 
  limestone 
  of 
  Thebes 
  is 
  seen 
  

   for 
  the 
  first 
  time 
  on 
  the 
  right 
  bank 
  above 
  Selsileh, 
  but 
  disappears 
  

   before 
  you 
  reach 
  the 
  sandstone-gorge 
  through 
  which 
  the 
  river 
  passes. 
  

   This 
  opening 
  is 
  made 
  in 
  a 
  ridge 
  of 
  fine-grained 
  sandstone 
  crossing 
  

   the 
  valley 
  almost 
  due 
  east 
  and 
  west. 
  At 
  the 
  entrance 
  to 
  the 
  river's 
  

   channel, 
  on 
  each 
  side, 
  for 
  some 
  distance, 
  are 
  great 
  banks 
  and 
  dome- 
  

   shaped 
  hillocks 
  of 
  alluvium, 
  evidently 
  washed 
  against 
  the 
  flanks 
  of 
  

   the 
  ridge 
  by 
  the 
  river 
  in 
  former 
  times 
  ; 
  as 
  usual, 
  these 
  are 
  covered 
  

   with 
  nodules 
  of 
  the 
  concretionary 
  tufaceous 
  substance. 
  On 
  the 
  right 
  

   bank 
  a 
  great 
  bed 
  of 
  alluvium 
  has 
  banked 
  up 
  what 
  had 
  evidently 
  

   been 
  an 
  old 
  river-channel, 
  as 
  the 
  Shells 
  found 
  in 
  the 
  neighbourhood 
  

   and 
  other 
  appearances 
  indicate. 
  Again, 
  abundance 
  of 
  Cyrenoz 
  were 
  

  

  * 
  Specimen 
  No. 
  7, 
  to 
  contrast 
  with 
  the 
  usual 
  sedimentary 
  deposit 
  No. 
  8. 
  

   t 
  Specimen 
  No. 
  9. 
  % 
  See 
  Specimen 
  No. 
  10. 
  

  

  VOL. 
  XX. 
  — 
  PART 
  I. 
  C 
  

  

  