Fossils in Great Britain

Brachiopod, Spirifer bisulcatus group © BGS

Fossils of one form or another can be found in virtually all of the sedimentary sequencences throughout the United Kingdom, and some unique igneous and metamorphic successions. Some sequences are relatively barren and may only contain fossils of microscopic size (microfossils), whilst in others fossils clearly visible to the naked eye (macrofossils) and of many different species can be found in abundance.

One method for the subdivision of rocks, biostratigraphy, is based on the identification of key fossils and fossil assemblages, and the recognition of how these change with time through successions of strata. Such biostratigraphical ‘zoning’ by means of fossils assists identification of strata where the sequence is not otherwise clear and acts as an additional check on correlations based on similar rock types. Correlation of strata using this approach allows relative dating of sequences and enables comparisons to be made between areas of the same age, but composed of dissimilar rocks.

Many fossil localities throughout the United Kingdom are key to recognising specific worldwide events in the geological history of the Earth and positioning the boundaries between different geological periods and era. These sites, along with similar sites in other countries, are used to correlate geological strata the world over.