paving vs subsurface

paving

noun
  • The hard durable surface placed directly atop the ground, as on a street or sidewalk. 

  • Interior pavement, as in a cathedral. 

adj
  • Pertaining to the material used for pavement, or to the surface itself. 

subsurface

noun
  • Something that is below the layer that is on the surface. 

  • A surface which is a submanifold of another surface. 

adj
  • below the surface 

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