Aymestrey Limestone

Aymestrey Limestone, a well-marked horizon in the Ludlow group of the Silurian system. It is a somewhat dark-gray concretionary rock, consisting of thin beds which attain a united thickness in places of 150 feet. It is well developed at Aymestrey, in Herefordshire, near Leominster, but thins off entirely at no great distance from that place. One of its most characteristic fossils is Pentamerus knightii, a brachiopod.