berg vs massif

berg

noun
  • mountain 

  • An iceberg. 

massif

noun
  • A principal mountain mass. 

  • A block of the earth's crust bounded by faults or flexures and displaced as a unit without internal change; normally consists of gneisses and schists 

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