﻿18 
  PROCEEDINGS 
  OP 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [ftov. 
  4, 
  

  

  found 
  on 
  terrace 
  -cliffs 
  throughout 
  the 
  river's 
  course, 
  especially 
  on 
  the 
  

   ridge 
  on 
  its 
  left 
  bank, 
  some 
  80 
  to 
  90 
  feet 
  above 
  the 
  most 
  ancient 
  of 
  

   the 
  temples 
  and 
  grottos, 
  and, 
  wherever 
  any 
  soil 
  has 
  been 
  left, 
  also 
  

   strewing 
  the 
  surface 
  of 
  the 
  loose 
  sand. 
  I 
  noticed 
  in 
  the 
  above 
  situa- 
  

   tion 
  several 
  great 
  rents 
  and 
  slips 
  in 
  the 
  rocks, 
  running 
  N.E. 
  and 
  

   S.W. 
  : 
  these 
  are 
  rarely 
  observed 
  in 
  the 
  sandstone, 
  unless 
  in 
  the 
  

   neighbourhood 
  of 
  the 
  granitic 
  protrusions, 
  none 
  of 
  which 
  could, 
  

   however, 
  be 
  seen, 
  at 
  least 
  in 
  the 
  neighbourhood 
  of 
  the 
  gorge. 
  With 
  

   reference 
  to 
  Sir 
  Gardner 
  Wilkinson's 
  hypothesis, 
  that 
  the 
  barrier 
  

   at 
  Selsileh 
  dammed 
  back 
  the 
  river 
  and 
  produced 
  the 
  rise 
  recorded 
  

   at 
  Semneh, 
  there 
  can 
  be 
  but 
  one 
  opinion. 
  When 
  the 
  locality 
  has 
  

   been 
  even 
  casually 
  examined, 
  it 
  is 
  evident 
  that, 
  supposing 
  the 
  height 
  

   of 
  the 
  river 
  to 
  have 
  been 
  equal 
  to 
  that 
  of 
  the 
  plateaus 
  above-men- 
  

   tioned, 
  its 
  waters 
  would 
  not 
  only 
  flow 
  through 
  the 
  large 
  gorges 
  

   right 
  and 
  left 
  of 
  the 
  present 
  entrance, 
  but 
  almost 
  top 
  the 
  ridge 
  

   altogether 
  ; 
  moreover, 
  granted 
  even 
  a 
  barrier 
  as 
  high 
  as 
  the 
  very 
  

   summit 
  of 
  the 
  ridge, 
  then 
  even 
  the 
  utmost 
  effect 
  on 
  the 
  rise 
  of 
  

   the 
  river 
  southwards 
  could 
  not 
  have 
  extended 
  beyond 
  a 
  few 
  miles. 
  

   I 
  believe 
  a 
  closer 
  examination 
  of 
  the 
  locality 
  than 
  I 
  had 
  an 
  oppor- 
  

   tunity 
  of 
  making 
  will 
  afford 
  more 
  convincing 
  proofs 
  of 
  the 
  impossi- 
  

   bility 
  of 
  any 
  obstacle 
  so 
  far 
  down 
  affecting 
  the 
  rise 
  of 
  the 
  river 
  even 
  

   at 
  the 
  First 
  Cataract. 
  

  

  After 
  leaving 
  Selsileh, 
  terrace 
  -cliffs 
  are 
  seen 
  running 
  along 
  both 
  

   banks 
  to 
  within 
  a 
  few 
  miles 
  of 
  Edfu, 
  and 
  wherever 
  the 
  hills 
  approach 
  

   the 
  river, 
  until 
  the 
  limestone 
  appears 
  near 
  Esneh, 
  where 
  the 
  river- 
  

   valley 
  opens 
  out 
  and 
  all 
  traces 
  of 
  high 
  grounds 
  are 
  lost. 
  

  

  III. 
  Conclusion. 
  — 
  From 
  the 
  evidences 
  adduced, 
  it 
  appears 
  to 
  me 
  

   that 
  there 
  is 
  reason 
  to 
  infer 
  that 
  the 
  Nile 
  in 
  early 
  ages 
  was 
  a 
  rapid 
  

   river 
  ; 
  and 
  that 
  the 
  force 
  of 
  the 
  stream 
  has 
  been 
  steadily 
  declining, 
  

   at 
  least 
  since 
  the 
  upheaval 
  (?) 
  of 
  the 
  valley 
  ceased 
  ; 
  therefore 
  the 
  

   wearing 
  process 
  has 
  diminished 
  : 
  for 
  this 
  reason 
  the 
  bottom 
  contains 
  

   more 
  mud, 
  and 
  in 
  consequence 
  may 
  even 
  be 
  rising, 
  on 
  the 
  whole 
  ; 
  

   and 
  this 
  latter 
  opinion 
  Sir. 
  Rhind 
  seemed 
  disposed 
  to 
  hold. 
  His 
  

   observations, 
  however, 
  tend 
  to 
  show 
  that 
  the 
  change 
  has 
  been 
  scarcely 
  

   perceptible 
  within 
  the 
  long 
  historical 
  period 
  furnished 
  by 
  the 
  records, 
  

   excepting, 
  as 
  already 
  shown, 
  at 
  certain 
  points, 
  caused 
  by 
  a 
  change 
  in 
  

   the 
  direction 
  of 
  the 
  river's 
  force 
  : 
  perhaps 
  a 
  similar 
  change, 
  or 
  the 
  

   giving 
  way 
  of 
  a 
  barrier 
  close 
  to 
  Semneh, 
  as 
  Mr. 
  Horner 
  remarks 
  *, 
  

   might 
  explain 
  the 
  fall 
  of 
  the 
  river 
  there. 
  

  

  * 
  " 
  Observations 
  on 
  the 
  Discovery, 
  by 
  Professor 
  Lepsius, 
  of 
  sculptured 
  marks 
  

   on 
  rocks 
  in 
  the 
  Nile 
  Valley 
  in 
  Nubia 
  ; 
  indicating 
  that, 
  within 
  the 
  historical 
  

   period, 
  the 
  river 
  had 
  flowed 
  at 
  a 
  higher 
  level 
  than 
  has 
  been 
  known 
  in 
  mcdern 
  

   times," 
  by 
  Leonard 
  Horner, 
  Esq., 
  F.K.S., 
  &c. 
  Edinburgh 
  New 
  Philosophical 
  

   Journal 
  for 
  July 
  1850. 
  

  

  See 
  also 
  ' 
  Letters 
  on 
  Egypt,' 
  &c, 
  by 
  Lepsius 
  (Bohn, 
  1853, 
  12mo), 
  pp. 
  30 
  and 
  

   238, 
  and 
  his 
  reply 
  to 
  Mr. 
  Horner's 
  " 
  Observations," 
  p. 
  530. 
  

  

  