Crug Farm Quarry

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Dyfed County

Geology & landscape

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

Description

Description The geological interest of this site, in technical terms, may be defined as follows: A richly fossiliferous shelly limestone, here contains abundant trilobites, brachiopods, conodonts, and echinoderm fragments. The Crûg Limestone is the only conodont-rich horizon at this level in Britain (the most recent age estimate is Cautleyan Zones 1/2), it has yielded important trilobite material, and is the type-locality of a number species. A key Upper Ordovician stratigraphic site. In layman's terms, the interest of this site may be expressed more simply, and such a statement is provided below. This should not be taken as definitive and further information as to details of the interest can be obtained from the Countryside Council for Wales . Although Crûg Quarry has been known to geologists for nearly 150 years recent research is proving that the site still has a great deal of new data to offer. Detailed study has revealed the presence of a rich and diverse assemblage of conodont microfossils which is considered unique in Britain for rocks of this age. On the basis of over thirty forms of conodont described from Crûg Farm, comparisons of this sequence have been made with strata of a similar age from various locations in Central America. Study has also been made of the other fossils recorded from Crûg Quarry and the site is now considered to be of key importance as a reference site for a number of species of trilobite.

Species mentioned