burian vs hummock

burian

noun
  • A barrow; mound; tumulus 

  • A camp; hill-fort. 

  • A tomb; sepulchre. 

hummock

noun
  • A small hill; a hillock; a knoll. 

  • A fistful. 

  • A ridge or hill of ice in an ice field. 

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