﻿J. 
  S. 
  Diller 
  — 
  Crater 
  Lake, 
  Oregon. 
  169 
  

  

  the 
  circuit 
  of 
  the 
  lake 
  from 
  which 
  they 
  radiate. 
  The 
  topmost 
  

   rocks 
  of 
  the 
  crest 
  are 
  planed 
  off 
  and 
  well 
  striated 
  upon 
  the 
  

   outer 
  slope, 
  but 
  not 
  upon 
  the 
  steep, 
  broken 
  surfaces 
  which 
  

   they 
  present 
  to 
  the 
  lake. 
  Glaciation 
  is 
  a 
  feature 
  of 
  the 
  outer 
  

   slope 
  only, 
  and 
  it 
  is 
  evident 
  that 
  the 
  ice 
  armed 
  with 
  stones 
  to 
  

   scratch 
  these 
  rocks 
  must 
  have 
  come 
  from 
  above, 
  that 
  is, 
  from 
  

   a 
  peak 
  which 
  once 
  stood 
  upon 
  the 
  site 
  of 
  the 
  lake. 
  

  

  In 
  the 
  deep, 
  U-shaped 
  canyons 
  of 
  Sun 
  and 
  Sand 
  Creeks 
  

   there 
  is 
  evidence 
  to 
  the 
  same 
  effect. 
  They 
  extend 
  directly 
  

   through 
  the 
  rim 
  to 
  the 
  brow 
  of 
  the 
  cliff, 
  over 
  500 
  feet 
  above 
  

   the 
  lake's 
  surface, 
  and 
  belong 
  to 
  a 
  system 
  of 
  drainage 
  which 
  

   has 
  been 
  completely 
  decapitated. 
  It 
  is 
  impossible 
  to 
  account 
  

   for 
  the 
  glacial 
  phenomena 
  and 
  drainage 
  features 
  of 
  that 
  region 
  

   on 
  the 
  supposition 
  that 
  its 
  topography 
  is 
  unchanged. 
  

  

  The 
  succession 
  of 
  lavas 
  and 
  the 
  system 
  of 
  dikes 
  point 
  to 
  a 
  

   volcanic 
  center 
  within 
  the 
  circle 
  of 
  the 
  rim 
  ; 
  but 
  the 
  structure 
  

   of 
  the 
  rim, 
  the 
  condition 
  of 
  its 
  inner 
  slope 
  and 
  its 
  glacial 
  phe- 
  

   nomena 
  go 
  a 
  step 
  further 
  and 
  suggest 
  that 
  during 
  the 
  glacial 
  

   period 
  the 
  lake 
  did 
  not 
  exist, 
  and 
  that 
  its 
  site 
  was 
  then 
  occu- 
  

   pied 
  by 
  a 
  huge 
  volcano 
  which 
  furnished 
  the 
  coulees 
  and 
  sheets 
  

   of 
  fragmental 
  material 
  in 
  the 
  rim, 
  as 
  well 
  as 
  the 
  masses 
  of 
  ice 
  

   and 
  snow 
  for 
  its 
  glaciation. 
  

  

  In 
  figure 
  1, 
  the 
  probable 
  outline 
  of 
  the 
  peak 
  is 
  indicated. 
  

   Judging 
  from 
  the 
  character 
  of 
  the 
  lava, 
  the 
  slopes 
  of 
  the 
  rim, 
  

   its 
  size 
  and 
  the 
  extent 
  of 
  its 
  glaciation, 
  it 
  is 
  reasonable 
  to 
  sup- 
  

   pose 
  that 
  Mt. 
  Mazama* 
  was 
  once 
  a 
  rival 
  of 
  Shasta 
  and 
  Rainier 
  

   for 
  the 
  supremacy 
  of 
  the 
  range. 
  

  

  The 
  greatest 
  feature 
  of 
  the 
  region 
  is 
  the 
  enormous 
  pit 
  or 
  

   caldera 
  containing 
  the 
  lake. 
  It 
  is 
  4,000 
  feet 
  deep, 
  extending 
  

   from 
  the 
  crest 
  of 
  the 
  Cascade 
  Range 
  down 
  half-way 
  to 
  the 
  

   sea-level. 
  More 
  than 
  a 
  square 
  mile 
  of 
  its 
  bottom 
  is 
  below 
  the 
  

   level 
  of 
  Klamath 
  Lake, 
  at 
  the 
  eastern 
  base 
  of 
  the 
  range. 
  

   The 
  pit 
  is 
  half 
  concealed 
  by 
  the 
  lake 
  which 
  so 
  greatly 
  beauti- 
  

   fies 
  the 
  scene. 
  

  

  The 
  volume 
  of 
  the 
  pit 
  is 
  nearly 
  a 
  dozen 
  cubic 
  miles, 
  and, 
  if 
  

   we 
  include 
  the 
  lost 
  peak, 
  it 
  would 
  possibly 
  be 
  half 
  again' 
  as 
  

   large. 
  The 
  problem 
  presented 
  for 
  solution 
  by 
  the 
  removal 
  of 
  

   such 
  an 
  enormous 
  mass 
  and 
  the 
  development 
  of 
  so 
  great 
  a 
  

   completely 
  enclosed 
  pit 
  in 
  the 
  process, 
  is 
  one 
  which 
  has 
  not 
  

   yet 
  been 
  completely 
  solved. 
  There 
  are, 
  however, 
  some 
  phe- 
  

   nomena 
  about 
  the 
  lake 
  that 
  throw 
  considerable 
  light 
  upon 
  it, 
  

   especially 
  when 
  taken 
  in 
  connection 
  with 
  those 
  of 
  similar 
  

   features 
  in 
  other 
  parts 
  of 
  the 
  globe. 
  

  

  The 
  composition 
  and 
  structure 
  of 
  the 
  mass 
  removed 
  con- 
  

   nects 
  its 
  transfer 
  at 
  once 
  with 
  volcanism, 
  and 
  the 
  form 
  of 
  the 
  

  

  * 
  The 
  " 
  ilazamas," 
  a 
  society 
  of 
  mountain-climbers 
  of 
  Portland. 
  Oregon, 
  met 
  at 
  

   ■Crater 
  Lake 
  last 
  summer, 
  and 
  christened 
  the 
  mountain, 
  whose 
  remnant 
  still 
  

   ■encircles 
  the 
  lake, 
  " 
  Mt. 
  Mazama." 
  

  

  