hummock vs tump

hummock

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

  • A fistful. 

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

tump

noun
  • A mound or hillock. 

  • A tumpline. 

verb
  • To form a mass of earth or a hillock around. 

  • To fall over. 

  • To draw or drag, as a deer or other animal after it has been killed. 

  • to bump, knock (usually used with "over", possibly a combination of "tip" and "dump") 

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