The Land Unknown

Navy Commander Alan Roberts is assigned to lead an expedition to Little America in Antarctica to investigate reports of a mysterious warm water inland lake discovered a decade earlier. His helicopter and its small party, including reporter Maggie Hathaway, is forced down into a volcanic crater by a fierce storm. They find themselves trapped in a lush tropical environment that has survived from prehistoric times.

• 
  Jock Mahoney

  Commander Harold 'Alan' Roberts
• 
  Shirley Patterson

  Margaret 'Maggie' Hathaway
• 
  William Reynolds

  Lt. Jack Carmen
• 
  Henry Brandon

  Dr. Carl Hunter
• 
  Douglas Kennedy

  Capt. Burnham
• 
  Phil Harvey

  Machinist's Mate Steve Miller
• 
  Kenner G. Kemp

  Officer at Briefing / Officer on Ship (uncredited)
• 
  Bing Russell

  Radio Operator (uncredited)
• 
  Bert Stevens

  Officer at Briefing (uncredited)