Subsoil.
The layer that contains the most humus and smaller rocks is the topsoil layer. Topsoil is the uppermost layer of soil that is rich in organic matter, such as humus, and contains smaller rock particles that have undergone weathering. It is the most fertile layer of soil and is crucial for plant growth.
bed rock
topsoil.
HUMUS . . . cures urvythang.
Soil is made up of a thin layer of weathered rock, humus, air, and water.
The layer of soil that has little or no humus in it is the subsoil. The top layer of the soil has the most humus in it because the dead leaves fall from the plant and go back into the soil. Water and sun also help give the plant humus.
The top layer of soil, called the O horizon or organic layer, contains humus. Humus is a dark, organic material that forms as plant and animal matter decomposes. It is rich in nutrients and helps improve soil structure and fertility.
topsoil
topsoil
The first layer is Litter, the third is Humus, so the second layer would be Duff.
The layer of solid rock beneath loose soil is called bedrock. This layer provides stability and support to the overlying soil and materials.