Here's a breakdown:

* Topsoil: The uppermost layer of soil, rich in organic matter, nutrients, and living organisms. It's crucial for plant growth.

* Subsoil: The layer beneath topsoil. It's typically denser and less fertile, containing more clay and minerals. It acts as a filter for water and nutrients moving to the topsoil.

There may be other layers beneath the subsoil, depending on the geological history and soil type. These layers are generally referred to as the C horizon and R horizon (bedrock).