Shoalshook Railway Cutting and Pit
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Geology & landscape
Geological Feature: Rock Outcrop · Mining / Industrial: Quarry · Geological Period: Ordovician · Rock Type: Limestone
Description
Description This, the type-locality of the Cautleyan-Rawtheyan (Ashgill) Shoalshook Limestone, is a classical geological section. Almost the entire succession of the limestone development of the Haverfordwest area is exposed, forming the most complete continuously exposed section in the outcrop area of the Shoalshook Limestone. The trilobite fauna includes a number of species for which this is the type-locality, and also a rich echinoderm-bearing horizon. Corals, brachiopods and rare graptolites are also present. The Shoalshook Limestone is of the highest value in British and international correlation in the Upper Ordovician. 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. The lineside and quarry exposures provide the standard reference section for the Shoalshook Limestone of Upper Ordovician age. These strata, which were deposited under marine conditions some 440 million years ago, have yielded an extremely diverse assemblage of fossils. Well preserved specimens or trilobites, corals, sea urchins and brachiopods have all been described from this locality; in addition, rare specimens of graptolites have also been recorded. In view of the abundance of fossils and the full sequence of beds exposed at this locality, Shoalshook has become an invaluable reference section for geological studies, both in Britain and overseas.