Geology Site Account

Summary

Site of Special Scientific Interest designated for the importance of its geology. This locality is the best exposure of the Harwich Stone Band, the most distinctive of the ash bands in the Harwich Formation at the base of the London Clay. The site extends along the foreshore from TM 263 316 to TM 263 323.

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Site description

This locality is particularly important as the best exposure of the Harwich Stone Band, the most distinctive of the ash bands in the Harwich Formation at the base of the London Clay which contains volcanic ash from explosive volcanic eruptions in Scotland during Eocene times some 50 million years ago. The stone band makes this part of the coast the only naturally occurring rocky shore along the entire distance between Norfolk and Kent and may even be the reason for the existence of the Harwich peninsula. The Harwich Stone Band contains attractive veins of green banded calcite (calcium carbonate) which can be cut and polished and is one of the few decorative stones native to Essex. Samuel Dale, the Essex naturalist and author of The History and Antiquities of Harwich and Dovercourt (1730), records that in his time the streets of Harwich were cobbled with dressed stones taken from this bed.

The foreshore is also of prime importance for London Clay fossils, particularly for fossil fruits and seeds from the Eocene rainforest. Also found are fossil sharks teeth amongst the beach shingle. Harwich is also famous for numerous fossils found by the workmen employed in the Harwich cement industry. These include some of the worlds first fossils of early mammals that were beginning to spread across the globe following the extinction of the dinosaurs. The most famous fossil found was Hyracotherium, the earliest ancestor of the horse (George 2010). Fossil fish and many giant fossil turtles were also found, several of which are on display in Ipswich and Norwich museums.

The fossils from Harwich have been collected and studied for more than 300 years making this an important site in the history of geology (see separate entry for Beacon Cliff).

Fossil collecting on the foreshore at Harwich. Photo © G.Lucy