The main difference is that diagram B experiences stress, while diagram A doesn't.
Explanation:
Diagram A is an example of rock strata that has not been disturbed by stress of any kind. It can be said that it presents superposition, meaning that the oldest rocks are at the bottom, while the youngest at the top.
Diagram B, on the other side, is an example of rock strata that experiences stress. The stress is horizontal, coming from the sides, causing the rocks to twist and bend, thus creating uplift on the surface.
