Rockhall Quarry

Also within

Herefordshire County

Condition (Natural England)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Silurian · Rock Type: Limestone

Description

Area, 1.6 ha. 3.9 ac. Description Rockhall Quarry, the type locality for the Aymestrey Limestone Group, displays rocks belonging to the Upper Bringewood and Lower Leintwardine Formations of the Ludlow Series of the Upper Silurian approximately 400 million years old. The quarry faces showa lateral transition within the Upper Bringewood Formation, from silty limestones in the east to calcareous siltstones in the west. This locality is of particular historical, as well as stratigraphical interest because this was one of the first sites where lateral change and diachroneity of facies was described. Diachroneity of facies is a term used to describe lateral variation of rock type through time. The site is also the type and only known locality for Inopinatella Lawsonii Elliott, a Silurian alga believed to be a primitive non calcareous dasycladacean, a form of blue green alga. As one of only two fully described non calcareous algae of Silurian age, it is of international importance for its contribution to the understanding of the evolution of the non vascular plants. The site also yields distinctive brachiopod assemblages, typical of the Upper Bringewood and Leintwardine Formations.