carr vs corcass

carr

noun
  • A bog or marsh; marshy ground, swampland. 

  • rock 

  • A marsh or fen on which low trees or bushes grow; a marshy woodland. 

corcass

noun
  • A riverine marsh in Ireland. 

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