﻿152 
  

  

  F. 
  A. 
  Perret 
  — 
  Some 
  Kilauean 
  Formations. 
  

  

  instances, 
  quite 
  — 
  perforating 
  the 
  roof. 
  If 
  this 
  occurs 
  in 
  the 
  

   earlier 
  stages 
  of 
  the 
  flow, 
  an 
  active 
  vent 
  is 
  formed, 
  emitting 
  

   much 
  gas 
  and 
  a 
  little 
  lava 
  in 
  spatters 
  or 
  driblets 
  which 
  build 
  

   up 
  a 
  " 
  blowing 
  cone 
  " 
  over 
  the 
  orifice. 
  When 
  the 
  action 
  is 
  

   violent, 
  and 
  especially 
  if 
  the 
  cone 
  has 
  formed 
  at 
  or 
  near 
  the 
  

   lava's 
  point 
  of 
  issue 
  on 
  the 
  crater 
  floor, 
  it 
  will 
  take 
  the 
  form 
  

   of 
  an 
  open 
  cylinder, 
  as 
  in 
  the 
  case 
  of 
  the 
  so-called 
  " 
  Little 
  

   Beggar" 
  (fig. 
  1), 
  and 
  the 
  lava 
  stream 
  will 
  then 
  have 
  the 
  appear- 
  

  

  FlG. 
  1. 
  

  

  Fig. 
  1. 
  The 
  " 
  Little 
  Beggar" 
  blowing 
  cone. 
  

  

  ance 
  of 
  flowing 
  from 
  the 
  base 
  of 
  the 
  cone. 
  A 
  more 
  moderate 
  

   activity 
  forms 
  a 
  simple 
  " 
  driblet 
  cone 
  " 
  (fig. 
  2) 
  in 
  which 
  the 
  

   central 
  conduit 
  may 
  be 
  closed 
  at 
  the 
  top 
  by 
  the 
  last 
  splashes 
  

   emitted 
  therefrom. 
  

  

  These 
  spatter 
  cones 
  have 
  always 
  constituted 
  a 
  conspicuous 
  

   feature 
  of 
  Kilauean 
  volcanism 
  and 
  testify 
  to 
  the 
  importance 
  of 
  

   the 
  gaseous 
  emanations 
  from 
  the 
  active 
  lava, 
  upon 
  which 
  there 
  

   has 
  been 
  so 
  great 
  a 
  tendency 
  to 
  cast 
  doubt. 
  They 
  are 
  also 
  

   interesting 
  as 
  demonstrating 
  that 
  the 
  same, 
  ultra 
  basic 
  lava 
  

   which, 
  flowing 
  continuously, 
  produces 
  a 
  cone 
  with 
  declivities 
  

   so 
  gentle 
  as 
  not 
  to 
  exceed, 
  in 
  some 
  cases, 
  four 
  or 
  five 
  degrees 
  

   will, 
  if 
  ejected 
  intermittently 
  in 
  splashes 
  which 
  cement 
  together 
  

   and 
  have 
  time 
  to 
  cool, 
  result 
  in 
  a 
  construction 
  whose 
  sides 
  may 
  

   even 
  attain 
  the 
  vertical 
  and 
  thus 
  exceed 
  the 
  repose 
  angle 
  of 
  the 
  

  

  