﻿2tt 
  H. 
  E. 
  Gregory 
  — 
  Gravels 
  at 
  Cuzco. 
  

  

  fan, 
  where 
  the 
  fields 
  may 
  have 
  been 
  cultivated 
  for 
  fi.ve 
  or 
  six 
  

   centuries, 
  soil 
  wash 
  and 
  associated 
  deposits 
  have 
  accumulated 
  

   to 
  depths 
  of 
  ten 
  to 
  twenty 
  feet 
  at 
  the 
  base 
  of 
  the 
  slopes. 
  A 
  

   section 
  exposed 
  on 
  the 
  bank 
  of 
  the 
  Ayahuaycco 
  Quebrada 
  pre- 
  

   sents 
  the 
  following 
  order 
  of 
  stratification 
  : 
  

  

  Recent 
  deposits 
  northwest 
  bank 
  of 
  Ayahuaycco 
  Quebrada. 
  

  

  Feet 
  

  

  1. 
  Wash 
  from 
  hill 
  slope 
  and 
  cultivated 
  field, 
  red-brown 
  

  

  in 
  tone, 
  composed 
  of 
  sand 
  and 
  clay 
  with 
  inclosed 
  

  

  rock 
  pebbles 
  and 
  earth 
  clods 
  ._ 
  1/4 
  

  

  2. 
  Ash, 
  cross-bedded 
  in 
  layers 
  1/4 
  to 
  1 
  inch, 
  composed 
  of 
  

  

  alternating 
  bands 
  of 
  black 
  charcoal, 
  burnt 
  grass, 
  

   etc., 
  and 
  grey 
  w 
  T 
  ood 
  ashes. 
  Fragments 
  of 
  bones, 
  

   teeth, 
  also 
  of 
  ancient 
  pottery, 
  are 
  abundant. 
  Near 
  

   the 
  base 
  pebbles 
  of 
  sandstone 
  and 
  thin 
  bands 
  of 
  

   sand 
  are 
  found 
  10 
  

  

  3. 
  Gravel, 
  rudely 
  stratified, 
  composed 
  of 
  pebbles 
  one 
  to 
  

  

  four 
  inches 
  in 
  diameter 
  ; 
  also 
  scattered 
  bones 
  and 
  

   sherds 
  . 
  _ 
  _'_ 
  8 
  

  

  4. 
  Sandstone 
  ledge, 
  on 
  top 
  of 
  which 
  lie 
  two 
  large 
  lime- 
  

  

  stone 
  bowlders 
  not 
  of 
  local 
  origin 
  .__ 
  4 
  

  

  The 
  thickness 
  of 
  cover 
  over 
  deposits 
  of 
  ashes 
  varies 
  from 
  

   one 
  to 
  eight 
  feet 
  within 
  a 
  distance 
  of 
  300 
  feet 
  along 
  the 
  Ayahu- 
  

   aycco 
  Quebrada. 
  The 
  thickness 
  and 
  position 
  of 
  deposits 
  of 
  

   human 
  origin 
  is 
  likewise 
  variable. 
  The 
  recent 
  date 
  of 
  the 
  

   wood 
  ash 
  and 
  overlying 
  strata 
  is 
  plainly 
  shown 
  by 
  the 
  pres- 
  

   ence 
  of 
  sherds 
  and 
  of 
  bones 
  of 
  modern 
  types 
  and 
  by 
  a 
  compari- 
  

   sion 
  of 
  the 
  ash 
  shown 
  in 
  section 
  along 
  the 
  quebrada 
  with 
  that 
  

   exposed 
  in 
  a 
  bank 
  300 
  feet 
  further 
  east. 
  In 
  structure 
  and 
  

   composition 
  the 
  two 
  are 
  essentially 
  alike, 
  although 
  one 
  is 
  the 
  

   present 
  city 
  dump 
  and 
  the 
  other 
  is 
  definitely 
  interbedded 
  with 
  

   gravels 
  and 
  soil 
  wash. 
  An 
  even 
  more 
  striking 
  illustration 
  of 
  

   aggradation 
  is 
  the 
  presence 
  along 
  the 
  lower 
  Ayahuaycco 
  of 
  a 
  

   wall 
  of 
  Incaic 
  or 
  pre-Incaic 
  design 
  which 
  had 
  been 
  buried 
  by 
  

   four 
  to 
  eight 
  feet 
  of 
  gravel, 
  partly 
  stream-laid, 
  partly 
  washed 
  

   from 
  the 
  slopes. 
  This 
  buried 
  wall 
  was 
  exposed 
  (about 
  1870) 
  

   in 
  cutting 
  an 
  artificial 
  channel 
  for 
  the 
  wet-weather 
  stream 
  

   which 
  drains 
  the 
  quebrada. 
  The 
  original 
  wall, 
  resting 
  on 
  

   what 
  is 
  believed 
  to 
  be 
  an 
  eroded 
  portion 
  of 
  the 
  fan, 
  is 
  com- 
  

   posed 
  of 
  hewn 
  limestone 
  blocks 
  of 
  excellent 
  workmanship 
  and 
  

   has 
  been 
  continued 
  upward 
  by 
  a 
  poorly 
  constructed 
  retaining 
  

   wall 
  of 
  stone 
  and 
  adobe 
  which 
  serves 
  as 
  a 
  border 
  for 
  the 
  fields 
  

   below.* 
  Similar 
  buried 
  walls 
  were 
  noted 
  at 
  other 
  localities, 
  

  

  * 
  For 
  further 
  details 
  regarding 
  this 
  wall 
  see 
  Bowman 
  : 
  " 
  A 
  Buried 
  Wall 
  at 
  

   Cuzco 
  and 
  its 
  Eelation 
  to 
  the 
  Question 
  of 
  a 
  pre-Inca 
  Eace," 
  this 
  Journal, 
  

   vol. 
  xxxiv, 
  pp. 
  497-509, 
  1912. 
  Bowman 
  concludes 
  that 
  the 
  burial 
  of 
  this 
  

   wall 
  may 
  date 
  from 
  2000 
  B. 
  C. 
  to 
  4000 
  B. 
  C. 
  Although 
  such 
  antiquity 
  is 
  

   possible, 
  yet 
  the 
  geological 
  conditions 
  are 
  satisfied 
  on 
  the 
  basis 
  of 
  a 
  much 
  

   shorter 
  period 
  of 
  time. 
  

  

  