Treffgarne Bridge Quarry
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Geology & landscape
Mining / Industrial: Quarry · Geological Period: Cambrian
Description
Description This disused quarry is the only site known to yield stratigraphically useful fossils in the so-called ‘Lingula Flags’ (in this area known as the Treffgarne Bridge Beds) of south-west Wales. The inarticulate brachiopod Lingulella occurs along with age-diagnostic trilobite species of Olenus and Homagnostus, indicating the presence of the lower Upper Cambrian Merioneth Series zones. This demonstrates the diachronous nature of the ‘Lingula Flags’ facies from south to north Wales. 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 Nature Conservancy Council. This site provides exposures of a group of rocks known as the Lingula Flags, which have a widespread distribution throughout Wales. Although these rocks take their name from a fossil brachiopod named Lingula, they sometimes contain other types of fossil which allow a more accurate date for the deposition of these rocks to be inferred. At Treffgarne Bridge the Lingula Flags contain two particular species of trilobite which are diagnostic of the Upper Cambrian portion of geological time, and which were laid down some 510 million years ago. It has been shown that at other locations in Wales the Lingula Flags are of slightly younger age, and this enables geologists to understand the changing palaeogeography of Wales during Cambrian times.