<span>There is six horizen.
1. O Horizon - The top, organic layer of soil,
2. A Horizon - The layer called topsoil;
3. E Horizon - This layer is beneath the A Horizon and above the
B Horizon. It is made up mostly of sand.
4. B Horizon - Also called the subsoil - this layer is beneath the E
Horizon and above the C Horizon.
5. C Horizon - it's called regolith: the layer beneath the B Horizon
and above the R Horizon.
6 R Horizon - this is last and the unweathered rock layer that is
beneath all the other layers.</span>
There are no appropriate units for power on the list you provided
I needed this ! Thanks a lot
