1. Topsoil (A Horizon): The uppermost layer, rich in organic matter (humus), minerals, and nutrients. It's the most fertile layer and supports plant growth.

2. Subsoil (B Horizon): Below the topsoil, it's less fertile and contains more clay, iron, and other minerals. It's where water percolates down from the topsoil, and it's often denser and more compact.

3. Parent Material (C Horizon): The deepest layer, consisting of the original rock material from which the soil developed. It can be weathered rock fragments, glacial deposits, or other materials.

Important Note: While these three layers are the main components, the soil profile can also include other layers, like a layer of organic matter on top of the topsoil called the O horizon or a hardpan layer called the E horizon between the topsoil and subsoil.