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.

• 
  Virgil W. Vogel
• 
  Joseph E. Kenney

• 
  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)
• 
  Tom Coleman
  Man at Briefing (uncredited)