* O Horizon (Organic Horizon): This is the topmost layer, made up of decomposed organic matter like leaves, twigs, and animal waste. It is often dark in color and rich in nutrients.

* A Horizon (Topsoil): This layer is a mixture of mineral particles and organic matter, forming the fertile topsoil. It is often dark in color due to the presence of humus (decomposed organic matter) and is where most plant roots grow.

* B Horizon (Subsoil): This layer is primarily composed of mineral particles and is often denser than the A Horizon. It may contain some organic matter from the layers above, and it is where clay and other minerals accumulate.

These are the three major horizons, but there can be other horizons as well, depending on the soil profile.