What is another word for sub-soils?
Pronunciation: [sˈʌbsˈɔ͡ɪlz] (IPA) 
Sub-soils is a term used to describe the layer of soil beneath the surface soil layer. Soils that are found beneath the topsoil can have different names depending on their characteristics. For example, in some regions, subsoils are referred to as subsoil horizons, or simply substratum or substrata. Some other synonyms for sub-soils include regolith, parent material, and horizon material. These synonyms are used when referring to the layer of soil which has not been affected by recent biological activity, and therefore, contains fewer organic matter content. In broader terms, these soils could be referred to as the lower soil layer or the B horizon.
