Mare’s Hill near Pulborough was a short-lived sand mine, dating from the beginning of the nineteenth century. The sand extracted was from the Pulborough Sand Rock, which underlies the Marehill Clay. The latter has an iron-cemented bed at its base, which forms the roof of the mine.
Records show the mine - which rarely extends beyond daylight - was active in 1918 and operated until around 1950 (records are inconsistent). The sand extracted was largely used to form mouldings for iron castings,but also used for the manufacture of tiles and bricks.
After the closure of the mine it was used for mushroom growing and is today an important hibernation site for bats. The site is looked after by the Sussex Wildlife Trust, through whom occasional access can be arranged.