landing stage vs molehead

landing stage

noun
  • A floating platform attached at one end to a wharf so as to rise and fall with the tide, and thus facilitate passage between the wharf and a vessel lying beside the stage. 

molehead

noun
  • A stone bulwark forming a haven or harbour; a breakwater. 

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