Ordovician Intrusive suite
Ordovician rocks in Herefordshire and Worcestershire are uncommon, occurring as small outcrops in northern Worcestershire and southern Herefordshire. The nature of Ordovician rocks in the two counties suggests an environment dominated by shallow marine conditions with volcanic activity occurring nearby.
During the Ordovician fine sediments were deposited in deep water. Igneous rocks were also intruded as dykes or sills. They cut through rocks of Cambrian and Ordovician age, but are not found in the May Hill Sandstone or younger rocks, so are presumed to be Ordovician in age. The intrusions have geochemical compositions ranging from doleritic to andesitic and have been variably metasomatised (chemically altered by sea water, hot fluids etc…).
Fowlet Farm Quarry, Herefordshire