crag vs scarp

crag

noun
  • A rocky outcrop; a rugged steep cliff or rock. 

  • A rough, broken fragment of rock. 

  • A partially compacted bed of gravel mixed with shells, of the Pliocene to Pleistocene epochs. 

scarp

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

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

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

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