The layer of soil that is partially weathered bedrock is called the regolith.

Here's a breakdown:

* Bedrock: The solid, unweathered rock that lies beneath the soil.

* Regolith: The layer of loose, unconsolidated material that sits on top of bedrock. This includes broken rock fragments, minerals, and other weathered materials.

* Soil: The uppermost layer of regolith, which has been further broken down and mixed with organic matter.

So, the regolith is the transitional layer between the bedrock and the true soil. It represents the initial stages of weathering where the bedrock has started to break down but hasn't yet become fully mixed with organic matter to form soil.