gravestead vs urnfield

gravestead

noun
  • The place where a grave or graves are located; a grave; a burial ground; cemetery. 

urnfield

noun
  • Ground used as a cemetery in Bronze Age Europe, in which the ashs of cremations were buried in cinerary urns. 

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