Folding- Folding occurs when tectonic processes put stress on a rock, and the rock bends, instead of breaking. This can create a variety of landforms as the surfaces of the folded rocks are eroded.
Anticlines are folds shaped like an arch, and synclines are shaped like the letter 'U.'
Geologists recognize these formations by what is visible at the surface. Look at the diagram of the syncline and notice how the surface shows a symmetrical pattern with the youngest rock in the middle and older rocks appearing on either side. Notice that the opposite is true of the anticline.