Editing Leatherhead (section)

===Geology===
Leatherhead is at the southern edge of the [[London Basin]], where the [[Permeability (Earth sciences)|permeable]] [[Chalk Group|upper chalk]] of the [[North Downs]] dips beneath the impermeable [[London Clay]].<ref name=Lhead_Geol>{{cite journal |last1= Lowther |first1= AWG |year= 1956 |title= A note on the geology of the Leatherhead district of Surrey |url= https://leatherheadhistoryarchive.org/wp-content/uploads/2019/04/VOL_1_NO_10_1956.pdf |journal=Proceedings of the Leatherhead & District Local History Society |volume= 1 |issue= 10 |pages= 11–13 |access-date= 4 February 2021}}</ref> The difference in properties between the two [[geological formation|formations]] results in a high [[water table]] and [[spring (hydrology)|springs]] are found at regular intervals along the boundary between them. Several settlements were established along this [[spring line settlement|spring line]] in [[Anglo-Saxons|Anglo-Saxon]] and early [[Middle Ages|medieval]] times, including the villages of [[Ashtead]], [[Fetcham]] and [[Effingham, Surrey|Effingham]], which are linked to Leatherhead by the Guildford to Epsom road.<ref name=Lhead_Geol/>