crag vs mons

crag

noun
  • A rocky outcrop; a rugged steep cliff or rock. 

  • A rough, broken fragment of rock. 

  • A partially compacted bed of gravel mixed with shells, of the Pliocene to Pleistocene epochs. 

mons

noun
  • A mountain or extinct volcano on a planet or a moon. 

  • The pubic mound or mons pubis. In human anatomy or in mammals in general, the mons pubis (Latin for "pubic mound"), also known as the mons veneris (Latin, mound of Venus) or simply the mons, is the adipose tissue lying above the pubic bone of adult females, anterior to the pubic symphysis. The mons pubis forms the anterior portion of the vulva. 

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