A syncline is a dip in a rocky layer that sinks inward from either side. It looks similar to a wave, but it is located in a rocky surface. This occurs because the older layers are located on the outer edges. Many of the rocks that are syncline also have rock layers. When the rock gains more layers, they get shoved to the center of the rock producing this wave-like effect.
The syncline can become a basin if the pattern becomes round or oval-shaped. A famous basin is the Powder River Basin. Another syncline is in the Great Lakes. These synclines were created by earthquakes or other movements in the surface. These synclines can be seen with the naked eye when looking at the way these rock layers come together.
