Editing William Morris Davis (section)

===Cycle of erosion theory===
Davis was a tenacious, as well as keen observer of nature, a master of logical deduction, and a brilliant synthesizer of disparate observations and ideas.<ref>{{cite news |last1=Koch |first1=Philip |title=William Morris Davis: Brief live of a pioneering geomorphologist: 1850-1934 |url=https://harvardmagazine.com/2018/09/william-morris-davis-cycle-of-erosion |website=Harvard Magazine |date=7 September 2018 |publisher=Harvard |access-date=16 September 2018}}</ref> From his own field observations and studies made by the original nineteenth-century surveyors of the western United States, he devised his most influential scientific contribution - the "[[cycle of erosion|geographical cycle]]". His theory first defined in his 1889 article, ''The Rivers and Valleys of Pennsylvania'',<ref name="Pruyne"/> which was a model of how [[river]]s erode uplifted land to [[base level]], was inspired by the work of Erasmus and [[Charles Darwin]] and [[Jean-Baptiste Lamarck]], and it had a strong evolutionary flavor {{Citation needed|date=March 2025}}. His cycle of erosion suggests that (larger) rivers have three main stages of development, generally divided into youthful, mature and old-age stages.<ref>Robert L Bates, Julia A Jackson, ed. ''Dictionary of Geological Terms: Third Edition'', p. 125 (1984)  [[American Geological Institute]]</ref> Each stage has distinct [[landform]]s and other properties associated with them, which can occur along the length of a river's upper, middle, and lower course.

Though the cycle of erosion was a crucial early contribution to the development of [[geomorphology]], many of Davis' theories regarding landscape evolution, sometimes termed 'Davisian geomorphology', were heavily criticized by later geomorphologists.  When Davis retired from Harvard in 1911, the study of landscape evolution was nearly monopolized by his theories.  It was characteristic of Davis to react violently and disdainfully to criticism, particularly to the German criticism in the 1920s headed by [[Walther Penck]]; it was also his characteristic to choose to attack the most vulnerable points of that criticism.<ref>Chorley ''et al''. 2005, p. 519</ref> Since that time, with a less dogmatic approach and greater knowledge, some authors note that Penck's and Davis' ideas have become more compatible and even complementary since the advent of [[Plate tectonics#History of the theory|modern tectonic theory]]. They claim that Davis' ideas are more applicable near [[active margin]]s where tectonics are "cataclysmic", and Penck's ideas fit better in models of [[passive margin]]s and [[Platform (geology)|continental platforms]].<ref name=Saadi>{{Citation| last  = Saadi| first = Allaoua| title = Modelos morfogenéticos e tectônica global: Reflexőes conciliatórias| journal = Geonomos| volume  = 6| issue   = 2| year    = 2013| pages   = 55–63| language = pt| url     = http://igc.ufmg.br/portaldeperiodicos/index.php/geonomos/article/viewFile/170/149}}</ref>