detritus vs flotsam

detritus

noun
  • Any debris or fragments of disintegrated material. 

  • Organic waste material from decomposing dead plants or animals. 

  • Pieces of rock broken off by ice, glacier, or erosion. 

flotsam

noun
  • Debris floating in a river or sea, in particular fragments from a shipwreck. 

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