What characterizes overturned rock layers?

Overturned rock layers are characterized by their tilt beyond vertical orientation. This means that the layers of rock, which originally formed in a horizontal position through processes like sediment deposition, have been subjected to tectonic forces that have caused them to tilt so much that they are effectively flipped over. This forms a situation where the top layers are now inclined steeply, sometimes even exceeding a vertical position, illustrating significant geological deformation.

The other options describe different properties of rock layers. For example, completely horizontal layers represent undisturbed sedimentary processes, while layers that exhibit no movement would imply stability and lack of tectonic activity. The notion of consisting of entirely different rock types refers more to stratigraphy or lithological variations, which does not specifically describe the structural condition of the layers like overturning does. Thus, option B accurately captures the unique characteristics of overturned rock layers.