heath vs overburden

heath

noun
  • A tract of level uncultivated land with sandy soil and scrubby vegetation; heathland. 

  • Many of the species in the genus Cassiope 

  • Any small evergreen shrub of the family Ericaceae. 

  • Both species in the genus Daboecia 

  • Any of the species in the genus Leucopogon, beard heath 

  • Coenonympha pamphilus, native to Europe, Asia except tropical India and Indochina, and Northern Africa, the small heath 

  • Many of the species in the genus Erica 

  • Coenonympha tullia, native to Europe, Asia except tropical India and Indochina, and North America, the large heath 

  • Any of the species in the genus Epacris, Australian heath 

  • Any of the species in the genus Phyllodoce, mountain heath 

  • Semiothisa clathrata, a moth known as the latticed heath 

  • Melitaea athalia, the heath fritillary 

overburden

noun
  • The rock and subsoil that lies above a mineral deposit such as a coal seam. 

  • A sterile stratum that lies above the stratum being investigated 

verb
  • To overload or overtax. 

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