hummock vs jebel

hummock

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

  • A fistful. 

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

jebel

noun
  • A hill, a mountain (especially in the Middle East or North Africa). 

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