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  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  EASTERN 
  SLOPE. 
  

  

  Atlantic 
  waters. 
  

   Valley 
  of 
  the 
  first 
  order. 
  — 
  South 
  Platte 
  River. 
  

  

  MOUNTAIN 
  GROUPS. 
  

  

  Group 
  of 
  first 
  order. 
  — 
  Pike's 
  Peaks. 
  

   Group 
  of 
  second 
  order. 
  — 
  Puma 
  Hills. 
  

   Group 
  of 
  third 
  order. 
  — 
  Basalt 
  Hills. 
  

  

  