cryptozoic vs unrevealed

cryptozoic

adj
  • Hidden (especially in the soil); not easily visible. 

  • Living in a cavity or small cave. 

  • Relating to a cryptozoite. 

unrevealed

adj
  • Not revealed; hidden; secret. 

How often have the words cryptozoic and unrevealed occurred in a corpus of books? (source: Google Ngram Viewer )