An extreme example of an overturned fold happens when the axial plane is horizontal and is called a recumbent fold. Monocline is a special kind of fold with only one limb. This can happen when sedimentary rocks sag over an underlying fault. Domes are circular or elliptical anticline resembling an inverted bowls. Sedimentary layering dips away from the center of a dome in all directions.
Basins are similar to domes.
They are syncline folds where the layering dips toward the center of the basin. Domes and basins can be small structures only a few kilometers in diameter but are often much larger. They result from regional warping of the entire continental crust. Fault Structures A fault is a structure with major displacement of rock material along a crack in a rock. This can occur when tectonic forces fractures the Earth's crust and rocks on opposite sides move past each other.