drumlin vs tump

drumlin

noun
  • An elongated hill or ridge of glacial drift. 

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 drumlin and tump occurred in a corpus of books? (source: Google Ngram Viewer )