﻿The 
  Nimrud 
  Crater 
  in 
  Turkish 
  Armenia. 
  139 
  

  

  the 
  Bendiniahi 
  and 
  Bitlis 
  rivers, 
  and 
  thus 
  brought 
  Lake 
  Van 
  into 
  

   being. 
  

  

  The 
  history 
  of 
  the 
  Nimrud 
  volcano 
  may 
  be 
  summarized 
  as 
  follows 
  

   from 
  the 
  speaker's 
  observations 
  : 
  — 
  

  

  1. 
  Its 
  forerunner 
  was 
  the 
  Kerkur 
  Dagh 
  on 
  its 
  southern 
  flank, 
  — 
  

   a 
  denuded 
  mass 
  of 
  grey 
  augite-trachyte, 
  rising 
  to 
  9000 
  feet, 
  and 
  

   crowned 
  by 
  many 
  peaks. 
  It 
  was 
  probably 
  erupted 
  in 
  the 
  Pliocene 
  

   Period, 
  subsequently 
  to 
  the 
  folding 
  of 
  the 
  Armenian 
  area, 
  in 
  which 
  

   the 
  latest 
  folded 
  rocks 
  are 
  of 
  Miocene 
  (Helvetian-Tortonian) 
  

   age, 
  occurring 
  north 
  of 
  the 
  Nimrud 
  Dagh 
  and 
  consisting 
  of 
  lime- 
  

   stones 
  with 
  corals 
  (Cladocora 
  artiadata, 
  Orbicella 
  defrancei, 
  &c), 
  

   Litliotli 
  amnion, 
  Foraminifera 
  (Lepidocycline 
  Orhitoides, 
  Ampin 
  - 
  

   stegina, 
  &c.)> 
  beds 
  of 
  Pecten 
  (P. 
  urmiensis, 
  &c.) 
  and 
  of 
  oysters 
  

   (Alectrj/onia 
  virleti). 
  Nimrud 
  and 
  the 
  other 
  numerous 
  volcanoes 
  

   of 
  Armenia 
  came 
  into 
  existence 
  at 
  a 
  period 
  when 
  the 
  sedimentary 
  

   rocks 
  could 
  no 
  longer 
  be 
  folded, 
  but 
  were 
  fractured 
  along 
  definite 
  

   hues, 
  and 
  Nimrud 
  is 
  situated 
  on 
  the 
  great 
  fracture 
  transverse 
  to 
  the 
  

   Armenian 
  folds 
  at 
  the 
  apex 
  of 
  their 
  bending 
  round 
  from 
  the 
  Anti- 
  

   tauric 
  (west-south-west 
  to 
  east-north-east) 
  to 
  the 
  Persian 
  (north- 
  

   west 
  to 
  south-east) 
  direction, 
  and 
  it 
  also 
  marks 
  the 
  point 
  of 
  inter- 
  

   section 
  of 
  this 
  fracture 
  with 
  a 
  great 
  north-east 
  to 
  north-west 
  

   fracture 
  (Caucasian 
  direction), 
  which 
  delimits 
  on 
  the 
  south 
  Lake 
  

   Van 
  and 
  the 
  faulted 
  depression 
  of 
  the 
  Plain 
  of 
  Mush, 
  abruptly 
  

   cutting 
  off 
  the 
  Tauric 
  horst 
  of 
  pre-Devonian 
  marbles 
  and 
  mica- 
  

   schists. 
  

  

  2. 
  Numerous 
  flows 
  of 
  augite-rhyolite 
  built 
  up 
  the 
  vast 
  cone 
  of 
  

   the 
  Nimrud 
  Dagh, 
  and 
  the 
  increasing 
  pressure 
  on 
  the 
  central 
  vent 
  

   became 
  relieved 
  by 
  extrusions 
  of 
  augite-trachyte 
  along 
  radial 
  

   fissures, 
  forming 
  the 
  present 
  promontories 
  of 
  Kizvag, 
  Zighag. 
  and 
  

   Karmuch. 
  

  

  3. 
  A 
  presumably 
  long 
  period 
  of 
  inactivity 
  was 
  followed 
  by 
  violent 
  

   explosions 
  destroying 
  the 
  summit 
  of 
  the 
  cone, 
  and 
  from 
  this 
  crater 
  

   (smaller 
  than 
  the 
  present 
  one) 
  vast 
  lava-flows 
  of 
  a 
  very 
  fluid 
  basalt 
  

   (crowded 
  with 
  phenocrysts 
  of 
  labradorite. 
  pale-green 
  augite, 
  and 
  

   some 
  olivine) 
  flooded 
  the 
  country 
  and 
  filled 
  up 
  the 
  Bitlis 
  and 
  

   Akhlat 
  valleys, 
  which 
  have 
  since 
  then 
  been 
  eroded 
  a 
  little 
  below 
  

   their 
  former 
  depth. 
  The 
  Sheikh 
  Ora 
  crater 
  of 
  basic 
  tuff 
  (now- 
  

   breached 
  by 
  Lake 
  Van) 
  probably 
  belongs 
  to 
  this 
  period. 
  

  

  4. 
  Further 
  explosions 
  widened 
  the 
  crater 
  in 
  which 
  a 
  large 
  lake 
  

   was 
  formed, 
  while 
  the 
  eastern 
  half 
  of 
  the 
  crater 
  became 
  filled 
  by 
  a 
  

   succession 
  of 
  outflows 
  of 
  augite-rhyolite. 
  in 
  which 
  numerous 
  blow- 
  

   holes 
  were 
  drilled, 
  bringing 
  to 
  the 
  surface 
  large 
  blocks 
  of 
  basaltic 
  

   agglomerate 
  and 
  also 
  affording 
  sections 
  showing 
  the 
  transition 
  

   downwards 
  from 
  obsidian, 
  spherulitic 
  obsidian, 
  and 
  spherulitie 
  

   rhyolite 
  to 
  banded 
  augite-rhyolite 
  (with 
  sanidine 
  and 
  green 
  augite 
  

   in 
  a 
  micropcecilitic 
  ground-mass). 
  

  

  •3. 
  The 
  last 
  eruption 
  was 
  recorded 
  in 
  1441 
  by 
  a 
  contemporary 
  

   Armenian 
  chronicler, 
  and 
  resulted 
  in 
  the 
  extrusion 
  of 
  a 
  very 
  viscous 
  

   augite-rhvolite 
  along 
  a 
  north-to-south 
  zone 
  of 
  weakness, 
  both 
  inside 
  

  

  