Editing Mountain (section)

===Erosion===
{{Main|Erosion}}
[[File:Valle Trebbia-(scaled-and-sharpened).jpg|thumb|right|[[Apennine Mountains]] and [[Trebbia]] river, Italy]]

During and following uplift, mountains are subjected to the agents of [[erosion]] (water, wind, ice, and gravity) which gradually wear the uplifted area down. Erosion causes the surface of mountains to be younger than the rocks that form the mountains themselves.<ref name=Fraknoi2004/>{{rp|160}} [[Glacier|Glacial processes]] produce characteristic landforms, such as [[pyramidal peak]]s, knife-edge [[arête]]s, and bowl-shaped [[cirque]]s that can contain lakes.<ref name="thornbury-1969">{{Cite book |last=Thornbury |first=William D. |title=Principles of geomorphology |publisher=Wiley |year=1969 |isbn=0471861979 |edition=2nd |location=New York |pages=358–376}}</ref> [[Plateau]] mountains, such as the [[Catskills]], are formed from the erosion of an uplifted plateau.<ref>{{Cite journal |last=Ver Straeten |first=Charles A. |date=July 2013 |title=Beneath it all: bedrock geology of the Catskill Mountains and implications of its weathering: Bedrock geology and weathering of the Catskills |journal=Annals of the New York Academy of Sciences |volume=1298 |pages=1–29 |doi=10.1111/nyas.12221 |pmid=23895551 |s2cid=19940868}}</ref>