-ferous vs -th

-ferous

suffix
  • Used to form adjectives from nouns, producing the specified material 

  • Used to form adjectives from nouns, containing the specified material 

-th

suffix
  • Used to form nouns from verbs of action. 

  • Used to form a term denoting the ordinal numeral corresponding to the value, being a natural number, of a mathematical expression. 

  • Used to form the ordinal numeral when the final term of the spelled number is not “first”, “second”, or “third”. 

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