Harefield Pit

{{short description|Site of Special Scientific Interest in Harefield, London}}

{{Infobox SSSI

|image=

|image_caption=

|name= Harefield Pit

|aos= Greater London

|interest= Geological

|gridref={{gbmappingsmall| TQ049898 }}

|area= 1.8 hectares

|notifydate=1990

|map=[http://magic.defra.gov.uk/MagicMap.aspx?startTopic=Designations&activelayer=sssiIndex&query=HYPERLINK%3D%271001658%27 Magic Map]

}}

Harefield Pit is a 1.8-hectare geological Site of Special Scientific Interest in Harefield in the London Borough of Hillingdon. It occupies much of a partially filled-in chalk quarry.{{cite web|url= https://designatedsites.naturalengland.org.uk/SiteDetail.aspx?SiteCode=S1001658&SiteName=harefield&countyCode=&responsiblePerson=&SeaArea=&IFCAArea= |title=Designated Sites View: Harefield Pit | series= Sites of Special Scientific Interest|publisher=Natural England|accessdate = 14 March 2021}}{{Cite web |url=http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001658.pdf |title=Natural England, Harefield Pit citation |access-date=2012-06-19 |archive-date=2012-10-24 |archive-url=https://web.archive.org/web/20121024045212/http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001658.pdf |url-status=dead }}{{cite web|url=http://magic.defra.gov.uk/MagicMap.aspx?startTopic=Designations&activelayer=sssiIndex&query=HYPERLINK%3D%271001658%27|publisher= Natural England|title= Map of Harefield Pit SSSI}} It has two entries in the Geological Conservation Review database.{{cite web|url=http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=519|title=Harefield (Palaeogene) |publisher =Joint Nature Conservation Committee|accessdate=15 January 2016}}{{cite web|url=http://jncc.defra.gov.uk/default.aspx?page=4174&gcr=762|title=Harefield (Tertiary Palaeobotany) |publisher =Joint Nature Conservation Committee|accessdate=15 January 2016}}

It is an important Tertiary site in the London Basin, which displays a sequence through the Upper Chalk, Reading Beds and London Clay. It is the only known source of charophytes in the Reading Beds, and these have potential for correlation with other localities in Europe.

Natural England has cast the site as "unfavourable declining" as the Reading Beds are not visible due to covering by vegetation.[https://designatedsites.naturalengland.org.uk/ReportUnitCondition.aspx?SiteCode=S1001658&ReportTitle=Harefield%20Pit%20SSSI Natural England, SSSI Unit information, Harefield Pit] It is set behind Lovett Road, without public access.