Editing Ur (section)

=== Prehistory ===
When Ur was founded, the Persian Gulf's water level was two-and-a-half metres higher than today. Ur is thought, therefore, to have had [[marsh]]y surroundings; irrigation would have been unnecessary, and the city's evident [[canal]]s likely were used for [[transportation]]. Fish, birds, tubers, and reeds might have supported Ur economically without the need for an [[Neolithic Revolution|agricultural revolution]] sometimes hypothesized as a prerequisite to urbanization.<ref>Jennifer R. Pournelle, "[https://www.researchgate.net/publication/257139948_From_KLM_to_Corona_A_Bird%27s_Eye_View_of_Cultural_Ecology_and_Early_Mesopotamian_Urbanization KLM to CORONA: A Bird's Eye View of Cultural Ecology and Early Mesopotamian Urbanization]"; in ''Settlement and Society: Essays Dedicated to Robert McCormick Adams'' ed. Elizabeth C. Stone; Cotsen Institute of Archaeology, UCLA, and Oriental Institute of the University of Chicago, 2007.</ref><ref>Crawford 2015, p. 5.</ref>

==== Prehistoric Ubaid period ====
Archaeologists have discovered evidence of early occupation at Ur during the [[Ubaid period]] (c. 5500–3700 BC), a [[prehistory|prehistoric]] period of [[Mesopotamia]].<ref>[https://isac.uchicago.edu/sites/default/files/uploads/shared/docs/saoc63.pdf] Carter, Robert A. and Philip, Graham, "Beyond the Ubaid: Transformation and Integration in the Late Prehistoric Societies of the Middle East", Studies in Ancient Oriental Civilization  63, The Oriental Institute of the University of Chicago, 2010 {{ISBN|978-1-885923-66-0}}</ref> The name derives from [[Tell al-'Ubaid]] where the earliest large excavation of Ubaid period material was conducted initially in 1919 by [[Henry Hall (Egyptologist)|Henry Hall]] and later by [[Leonard Woolley]].<ref>Henry R.H. Hall, C.L. Woolley, et al., [http://digital.library.stonybrook.edu/cdm/ref/collection/amar/id/13075 "Al 'Ubaid", 1927]</ref><ref>Hall, Henry R. and Woolley, C. Leonard. 1927. ''Al-'Ubaid. Ur Excavations 1''. Oxford: Oxford University Press.</ref>

Later, a layer of soil covered the occupation levels from the Ubaid period. Excavators of the 1920s interpreted the layer of soil as evidence for the [[Flood myth|Great Flood]] of the [[Epic of Gilgamesh]] and [[Book of Genesis]]. It is now understood that the South Mesopotamian plain was exposed to regular floods from the [[Euphrates]] and the [[Tigris]] rivers, with heavy [[erosion]] from water and wind, which may have given rise to the Mesopotamian and derivative Biblical Great Flood stories.<ref name="Nova">{{cite web |title=Secrets of Noah's Ark – Transcript |url=https://www.pbs.org/wgbh/nova/video/secrets-of-noahs-ark |website=Nova |publisher=PBS |access-date=27 May 2019 |date=7 October 2015}}</ref>