orography vs township

orography

noun
  • the orographic features of a region 

  • the scientific study, or a physical description of mountains 

township

noun
  • The territory of a town. 

  • A nonwhite (usually subeconomic) area attached to a city. 

  • A small town. 

  • A subdivision of a county. 

  • An area set aside for nonwhite occupation. 

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