There are various Gideon Mantell family archives and letters in the East Sussex record office and a visit was arranged for Sat 15th May 2010. This visit has now happened many thanks to Isilda and the record office for all the documents they arranged for us to see.
If you wish to consult the archives there ask to see the microfilm of archives held in New Zealand at XA 64. There are various records under the location GIL/4/42/7/116/1-24 including those which relate to his becoming a Fellow of the Royal Society. There are records of his time as a Poor Law Doctor in Lewes under PAR412/35/2-3.
This was followed by walk 2 in the series “Roman finds at St John sub Castro?” Gideon Mantell recorded finding two Imperial coins in the churchyard but other evidence of a Roman settlement is sparse. This walk explored some of the theories around the earliest Lewes settlement and tried to locate the evidence. It included a visit to the the grave of Thomas and Sarah Mantell who were buried in the churchyard at St John sub Castro. see picture above.