profile - a vertical section of the Earth's crust showing the different horizons or layers

horizon - a specific layer or stratum of soil or subsoil in a vertical cross section of land

A horizon, A-horizon - the top layer of a soil profile; usually contains humus

B horizon, B-horizon - immediately below the A-horizon; contains deposits of organic matter leached from surface soils

C horizon, C-horizon - beneath the B-horizon and above the bedrock; consisting of weathered rock