Offham Chalk Pit, near Lewes, East Sussex

Image: © Adrian Diack Taken: 13 Dec 2025

The photo shows a partial view of the largest of the Offham Chalk Pits near Lewes which is an historic location for a number of reasons including being visited by Dr Gideon Mantell; that fossils from it include rare forms of Micraster unique to Britain and that the working of the quarry has left a legacy of industrial archaeology which is an interesting feature in its own right. Gideon Mantell was born in St Mary’s Lane now Station Street in Lewes and from a young age he enjoyed nothing more than collecting fossils in the area round Lewes. In adult life, too, his passion burned even brighter for as he wrote in “The Fossils of the South Downs” “….I resolved to devote my leisure moments to the investigation of the organic remains of a former world; a study replete with interest and instruction.” Offham Chalk Pit lies less than 2 miles distant from the centre of Lewes where Dr Mantell came to live and practice medicine. The pit had locational advantages in that it had a nearby town as a source of labour, a nearby road for access and nearby access to the River Ouse and its barge traffic that could be used to transport the heavy burnt lime produced by the kilns. The pit began to be worked from about 1793 and as it developed a funicular railway was built in 1808 by George Shiffner and William Jessop to take the quicklime from the kilns down under the road to the waiting barges on the River Ouse. A tramway linked the kilns to a wharf on a branch line of the Upper Ouse Navigation and this is thought to be part of the oldest railway in Sussex. Due to its efficiency and economic design the railway survived until 1870 which is when the chalk pit ceased operations. Offham Chalk Pits were first developed for lime and then for chalk embankments to help with navigation on the River Ouse. Dr Mantell and his wife Mary were to become famous for their discovery and naming of the first plant eating dinosaur Iguanodon and other dinosaurs at Whitemans Green Quarry in Cuckfield, but they also collected representative fossils from the Lewes Upper Chalk Formation near Lewes. Dr Mantell noted that “Offham Pit, is nearly two hundred foot high, and exhibits a good section of the chalk. It contains the large fibrous bivalve, the fragments of which are so frequently met with in every locality; teeth and plates of fishes, and numerous zoophytes. It is the only locality near Lewes, in which Marsupites have been discovered.” (I suggest the commonly found shell that he referred to is likely to have been the Lower Turonian to Middle Coniancian bivalve of the genus, Inoceramus, which is named from the Greek for fibrous shell and is a key index fossil.)

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