groundlaying vs substratal

groundlaying

adj
  • Of, pertaining to, or supplying a foundation; foundational; fundamental. 

noun
  • The creation of a foundation or base. 

  • The first process in decorating by means of enamelled colour. 

substratal

adj
  • Of or pertaining to a substratum. 

  • Specifically, pertaining to a substrate language. 

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