massif vs mountain chain

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 

mountain chain

noun
  • A series of mountain ranges stretching across a continent. 

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