Nash Quarry

Exposed Units: Folly Sandstone, Nash Scar Limestone, Coalbrookdale Formation

This is a large quarry in Nash Scar Limestone and Folly Sandstone with faulting associated with the Church Stretton Fault System.  Huge cliffs of crystalline limestone show corals, bryozoans and brachiopod fossils.  The older Folly Sandstone is seen in the core of an anticline.  Both rocks are affected by a variety of minor faults.  At this site the Folly Sandstone contains thick-bedded pebbly sandstones which have yielded some brachiopod fossils.

Nash Scar Limestone contains calcareous algae and bryozoan fossils within a coarse, calcite-bearing groundmass.  These algal limestones accumulated in an area of shallow sea, resulting from uplift along the line of the Church Stretton Fault.  The limestones are equivalent to the Woolhope Limestone.

The overlying Coalbrookdale Formation mudstones were formerly exposed to southeast of the site.

Photos

General view of the exposure at Nash Quarry.

The boundary between the interbedded sandstones and shales of the Folly Sandstone (bottom) and the overlying Nash Scar Limestone (top).

References

Hurst, J.M., Hancock, N.J. and McKerrow, WS. 1978. ‘Wenlock stratigraphy and palaeogeography of Wales and the Welsh Borderland’, Proceedings of Geologist’s Association,vol. 89, 3, pp. 197-226.

Pocock, R.W., Brammall, A. and Croft, W.N., 1940, ‘Easter field meeting, Hereford, 6 to 12 April 1939’,  Proceedings of Geologist’s Association, vol. 51, 1, pp. 52-62.

Woodcock, N.H. and Bassett, M.G. (eds)., 1993, Geological excursions in Powys, Central Wales, University of Wales Press, Cardiff, pp. 366.

Ziegler, A.M., Cocks, L.R.M. and McKerrow, W.S., 1968, ‘The Llandovery transgression of the Welsh Borderland’, Palaeontology, vol. 11, pp. 736-782.

March 2011