﻿Titicaca 
  Island 
  and 
  Adjoining 
  Areas. 
  197 
  

  

  Titicaca 
  Island. 
  — 
  Titicaca 
  Island 
  is 
  a 
  representative 
  of 
  a 
  

   large 
  class 
  of 
  elevations 
  including 
  hogbacks, 
  eroded 
  folds, 
  

   mesas, 
  igneous 
  masses, 
  and 
  probably 
  fault 
  blocks, 
  which 
  pro- 
  

   ject 
  above 
  the 
  general 
  floor 
  of 
  the 
  great 
  interior 
  basin 
  or 
  pla- 
  

   teau. 
  In 
  common 
  with 
  its 
  companions 
  it 
  has 
  reached 
  a 
  mature 
  

   stage 
  of 
  development 
  and 
  is, 
  in 
  brief, 
  a 
  residual 
  prominence 
  

   now 
  partly 
  submerged 
  in 
  the 
  waters 
  of 
  a 
  lake. 
  

  

  In 
  outline 
  Titicaca 
  Island 
  is 
  very 
  irregular 
  (fig. 
  8). 
  Five 
  

   large 
  bays 
  set 
  deeply 
  into 
  the 
  land, 
  in 
  addition 
  to 
  ten 
  or 
  twelve 
  

   other 
  bays 
  of 
  one-fourth 
  mile 
  or 
  less 
  in 
  width 
  which 
  scallop 
  

   the 
  island's 
  border. 
  Although 
  the 
  island 
  has 
  an 
  area 
  of 
  102 
  

   square 
  miles, 
  with 
  an 
  extreme 
  length 
  of 
  only 
  seven 
  miles, 
  and 
  

   width 
  nowhere 
  exceeding 
  three 
  miles, 
  the 
  length 
  of 
  the 
  coast 
  

   line 
  is 
  33 
  miles. 
  Only 
  at 
  the 
  southwest, 
  where 
  the 
  sandstone 
  

   ridge 
  of 
  Kakayo-Kena 
  forms 
  an 
  unbroken 
  wall 
  for 
  nearly 
  five 
  

   miles, 
  does 
  the 
  coast 
  assume 
  a 
  rectilinear 
  quality. 
  

  

  The 
  dominating 
  feature 
  of 
  the 
  island's 
  surface 
  is 
  a 
  backbone 
  

   or 
  central 
  ridge, 
  extending 
  from 
  Bilcokyma 
  to 
  Sicuyo, 
  a 
  distance 
  

   of 
  about 
  seven 
  miles, 
  and 
  following 
  the 
  direction 
  of 
  strike 
  of 
  

   the 
  sedimentaries 
  which 
  compose 
  it. 
  On 
  the 
  northeast 
  the 
  

   Kea 
  Kollu 
  dome, 
  extending 
  far 
  into 
  the 
  lake, 
  assumes 
  a 
  com- 
  

   manding 
  position, 
  and 
  on 
  the 
  southwest 
  the 
  long, 
  straight 
  

   ridge 
  of 
  Kakayo-Kena, 
  culminating 
  at 
  Chullun-Kayani 
  with 
  an 
  

   elevation 
  of 
  800 
  feet, 
  constitutes 
  a 
  conspicuous 
  feature 
  of 
  the 
  

   landscape. 
  At 
  the 
  north 
  the 
  peninsula 
  of 
  Marcuni, 
  tied 
  to 
  the 
  

   land 
  by 
  the 
  low 
  isthmus 
  of 
  Challa, 
  is 
  a 
  prominent 
  feature 
  when 
  

   viewed 
  from 
  the 
  lake. 
  Approximately 
  two-thirds 
  of 
  the 
  

   island 
  maintains 
  a 
  height 
  of 
  100-500 
  feet, 
  a 
  few 
  small 
  areas 
  

   are 
  over 
  TOO 
  feet, 
  and 
  at 
  Falla-Kasa 
  a 
  barometer 
  reading 
  of 
  

   13,330 
  feet, 
  830 
  feet 
  above 
  lake 
  level, 
  was 
  obtained. 
  This 
  is 
  

   probably 
  the 
  culminating 
  point 
  on 
  the 
  island, 
  and 
  Squier's 
  

   figure, 
  2,000 
  feet, 
  for 
  the 
  hills 
  back 
  of 
  Challa 
  is 
  clearly 
  an 
  

   error. 
  Back 
  from 
  the 
  shore 
  the 
  surface 
  has 
  little 
  sharp 
  relief; 
  

   cliffs 
  and 
  precipices 
  and 
  deeply 
  cut 
  chasms, 
  except 
  those 
  

   formed 
  by 
  differential 
  erosion 
  of 
  strata, 
  are 
  absent. 
  Rounded 
  

   ridges, 
  flattened 
  domes, 
  flat 
  saddles, 
  and 
  graded 
  slopes 
  form 
  

   the 
  surface, 
  but 
  not 
  to 
  the 
  exclusion 
  of 
  minor 
  steep 
  rock 
  

   slopes 
  developed 
  on 
  the 
  edges 
  of 
  tilted 
  strata. 
  In 
  fact 
  dip 
  

   slopes 
  and 
  cuesta 
  fronts 
  in 
  many 
  places 
  determine 
  the 
  topog- 
  

   raphy 
  and 
  point 
  to 
  structural 
  control 
  of 
  subordinate 
  features. 
  

   The 
  valleys 
  separating 
  the 
  rounded 
  heights 
  are 
  broad 
  Y-shaped, 
  

   frequently 
  nearly 
  flat, 
  and 
  the 
  divides 
  are 
  everywhere 
  incon- 
  

   spicuous. 
  Only 
  in 
  their 
  lower 
  courses 
  do 
  the 
  stream 
  channels 
  

   become 
  steep-walled 
  ditches 
  and 
  then 
  only 
  where 
  wave-worn 
  

   headlands 
  have 
  destroyed 
  previously 
  established 
  grades. 
  In 
  

   short, 
  the 
  topography 
  is 
  mature 
  or 
  post-mature 
  and 
  youthful 
  

   features 
  are 
  exceptional. 
  (See 
  figs. 
  1, 
  5 
  and 
  6.) 
  

  

  