hoodmould vs speleothem

hoodmould

noun
  • The outermost moulding which protrudes out of a wall over an archway (over the hood of a door, window or other opening), for decoration or the cover transitions between surfaces, and to discharge rain; a dripstone. 

speleothem

noun
  • Any secondary mineral, deposited in a natural cave by the action of water. 

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