Peneplain
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A peneplain is the final stage in fluvial or stream erosion. After the streams in an area have reached base level, lateral erosion is dominant as the streams erode the highland areas between them. Finally, virtually all of the upland is gone and the stream floodplains merge in an area of very low to no topographic relief. Essentially the result is a flat plain which is the ultimate stage in the cycle of erosion or geographical cycle. The streams within a peneplained region show extensive meandering and braiding. If the area is subsequently uplifted due to adjacent orogenic processes without internal deformation within the peneplain, the streams will again begin downward erosion and create incised meanders, water gaps, and other unique geomorphic features. The concept was developed by the early geomorphologists William Morris Davis and Walther Penck in the early 1900s. A peneplain can be mistaken for a depositional plain. However, the rocks beneath a peneplain have been folded and tilted by tectonic forces, while the rocks beneath a plain lie in horizontal layers.