The Aymestry Limestone Formation is a fossiliferous limestone of Gorstian age (Upper Silurian) deposited in a warm shallow sea near the eastern margin of the Iapetus Ocean. It occurs in England in the Ludlow Group, between the Upper and Lower Ludlow Shales. It derives its name from Aymestrey (sic), Herefordshire, where it may be seen on both sides of the River Lugg. It is well developed in the neighbourhood of Ludlow (it is sometimes called the Ludlow limestone) and occupies a similar position in the Ludlow shales at Woolhope, the Abberley Hills, May Hill and the Malvern Hills.