cœmeterium vs urnfield

cœmeterium

noun
  • An ancient cemetery, churchyard, or burial ground. 

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 cœmeterium and urnfield occurred in a corpus of books? (source: Google Ngram Viewer )