﻿APR. 
  4, 
  1922 
  BROUWER: 
  tectonic 
  features 
  dutch 
  east 
  liNDlES 
  177 
  

  

  consists 
  principally 
  of 
  basic 
  eruptive 
  rocks 
  and 
  in 
  the 
  southern 
  part 
  

   crystalline 
  schists, 
  whose 
  main 
  strike 
  is 
  insufficiently 
  known, 
  are 
  of 
  

   widespread 
  occurrence. 
  In 
  the 
  narrow 
  portion 
  of 
  the 
  island, 
  which 
  

   connects 
  the 
  northern 
  peninsula 
  with 
  the 
  central 
  part, 
  some 
  authors 
  

   have 
  presumed 
  that 
  there 
  exists 
  a 
  main 
  strike 
  from 
  south 
  to 
  north, 
  

   which 
  would 
  bend 
  to 
  an 
  east-westerly 
  direction 
  in 
  the 
  northern 
  penin- 
  

   sula. 
  But 
  the 
  region 
  consists 
  principally 
  of 
  crystalline 
  schists 
  and 
  

   eruptive 
  rocks 
  and 
  no 
  folded 
  Tertiary 
  rocks 
  are 
  known, 
  while 
  a 
  north- 
  

   west-southeast 
  strike 
  seems 
  to 
  prevail. 
  It 
  is 
  possible 
  that 
  the 
  pro- 
  

   longation 
  of 
  the 
  parallel 
  ranges 
  in 
  the 
  adjacent 
  projecting 
  part 
  of 
  

   Borneo 
  crosses 
  this 
  part 
  of 
  Celebes 
  obliquely 
  and 
  that 
  the 
  supposed 
  

   bending 
  of 
  the 
  Tertiary 
  strike 
  does 
  not 
  exist. 
  Thus 
  viewed, 
  the 
  

   Tertiary 
  mountain-plan 
  of 
  the 
  island 
  may 
  be 
  thought 
  of 
  as 
  comprising 
  

   two 
  strongly 
  diverging 
  trend 
  lines 
  of 
  which 
  the 
  northern 
  recurves 
  to 
  the 
  

   north 
  in 
  the 
  direction 
  of 
  one 
  of 
  the 
  trend 
  lines 
  of 
  the 
  Philippine 
  islands. 
  

   To 
  repeat, 
  particularly 
  in 
  that 
  part 
  of 
  the 
  Archipelago 
  which 
  is 
  occupied 
  

   bv 
  the 
  Island 
  of 
  Celebes 
  there 
  are 
  important 
  differences 
  between 
  the 
  

   Tertiary 
  strike 
  and 
  the 
  direction 
  of 
  the 
  present 
  geanticlinal 
  axes. 
  

  

  The 
  geologic 
  plan 
  of 
  Borneo 
  in 
  many 
  respects 
  resembles 
  that 
  of 
  

   Celebes 
  in 
  that 
  it 
  is 
  not 
  well 
  explained 
  by 
  a 
  "side 
  and 
  end-on" 
  conflict 
  

   of 
  folded 
  ranges, 
  but 
  on 
  the 
  contrary 
  suggests 
  the 
  existence 
  of 
  a 
  system 
  

   of 
  branching 
  trend 
  lines 
  similar 
  to 
  that 
  of 
  the 
  present 
  Philippine 
  islands. 
  

   From 
  the 
  northeastern 
  part, 
  where 
  the 
  highest 
  elevations 
  of 
  the 
  island 
  

   occur 
  and 
  where 
  the 
  folded 
  ranges 
  with 
  a 
  main 
  trend 
  north-northeast 
  

   to 
  south-southwest 
  are 
  closely 
  crowded 
  together, 
  the 
  main 
  strikes 
  

   diverge 
  to 
  the 
  southwest. 
  The 
  eastern 
  trend 
  lines 
  bend 
  to 
  the 
  south- 
  

   west 
  in 
  the 
  direction 
  of 
  Celebes, 
  those 
  more 
  to 
  the 
  west 
  first 
  have 
  a 
  

   direction 
  from 
  north 
  to 
  south, 
  but 
  bend 
  to 
  the 
  southwest, 
  while 
  the 
  

   central 
  and 
  western 
  ranges 
  recurve 
  to 
  the 
  northwest, 
  almost 
  at 
  right 
  

   angles 
  to 
  their 
  general 
  course 
  in 
  the 
  northeastern 
  part 
  of 
  the 
  island. 
  

  

  The 
  plan 
  of 
  vSumatra 
  is 
  similar 
  to 
  that 
  of 
  Borneo, 
  although 
  the 
  

   branching 
  of 
  the 
  trend 
  lines 
  is 
  not 
  so 
  distinctly 
  pronounced. 
  The 
  high- 
  

   est 
  altitudes 
  of 
  the 
  older 
  rocks 
  occur 
  in 
  the 
  northwestern 
  part 
  of 
  the 
  

   island 
  and 
  the 
  main 
  trend 
  lines 
  diverge 
  to 
  the 
  southeast. 
  

  

  The 
  reconstruction 
  of 
  the 
  main 
  older 
  trend 
  lines 
  in 
  the 
  eastern 
  part 
  

   of 
  the 
  Archipelago 
  cannot 
  be 
  made 
  complete, 
  because 
  that 
  part 
  of 
  

   the 
  region 
  is 
  mostly 
  covered 
  by 
  the 
  sea 
  and 
  older 
  folds 
  in 
  many 
  places 
  

   are 
  cut 
  off 
  by 
  the 
  present 
  coast 
  lines. 
  There 
  are, 
  however, 
  some 
  

   indications 
  that 
  virgations 
  also 
  occur 
  here. 
  In 
  the 
  islands 
  of 
  the 
  Kei 
  

  

  