puy vs tor

puy

noun
  • Any of several cone-shaped hills in the Auvergne, France that are the remains of extinct volcanos 

  • Any similar conical structure of volcanic material 

tor

noun
  • A hill with such rock formation. 

  • A craggy outcrop of rock on the summit of a hill, created by the erosion and weathering of rock. 

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