subsoil

Excavators are then used to dig out the top soil and subsoil.

Taiwan’s religious diversity and vitality forms a kind of subsoil of the self-governed island’s identity and values.

If you dig a burial pit into the subsoil, when you take the dead out and backfill it, the soil will be a different color.

This man’s house is located in a region with dense clay subsoil.

Biological traces from animal and plant material in the subsoil consist of carbon.