foothill vs scarp

foothill

noun
  • A hill at the base of a mountain or mountain range. 

scarp

noun
  • The steep artificial slope below a fort's parapet. 

  • A cliff at the edge of a plateau or ridge caused by erosion or faulting; the steeper side of an escarpment. 

verb
  • to cut, scrape, erode, or otherwise make into a scarp or escarpment 

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