Here's why:

* Bedrock is the solid, unweathered rock that lies beneath all soil horizons.

* C horizon is the layer of soil that is partially weathered, meaning it's still undergoing the process of breaking down from bedrock.

* The C horizon lies *above* the bedrock.

Think of it like this:

1. Bedrock: The foundation, the solid rock.

2. C horizon: The partially broken-down rock, a transition zone between bedrock and the more developed soil layers.

3. B horizon: The layer where minerals and organic matter have accumulated.

4. A horizon: The topsoil, where most biological activity happens.

So, while the C horizon is related to the bedrock because it's formed from it, it's not the bedrock itself.