Block Mountains are formed from the motions of the inner earth.
As the stress forces operate on the rocks they build faults in them.
If the land is elevated above the surrounding areas between the two nearly parallel faults it forms a block mountain.
It can also occur when land falls down on the outer side of the faults leaving an elevated block between them.
The rocks that make up the fault levels can be smooth or even folded.
Block Mountain is also called a horse:
Examples of Block Mountains:
The Vosges (France)
Black Forest Mountains (Germany)
Sierra Nevada (North America)