South Thames Estuary and Marshes South Thames Estuary and Marshes South Thames Estuary and Marshes is a biological Site of Special Scientific Interest which stretches between Gravesend and the mouth of the River Medway in Kent. Part of it is a Nature Conservation Review site, Grade I, and part is a Royal Society for the Protection of Birds nature reserve. It is part of the Thames Estuary and Marshes Ramsar internationally important wetland site and Special Protection Area under the European Union Directive on the Conservation of Wild Birds. Over 20,000 waterfowl use this site, and some species are present in internationally important numbers. There
Canvey Island location of land areas in Ptolemy's ancient work have led modern researchers to question the correlation between Ptolemy's island and contemporary Canvey. MacBean and Johnson, 18th century historians, contend "Counus Island" would have existed much further out to sea (or even likely to be the Isle of Sheppey), so any similarity between the names is mere coincidence. Without any suitable island matching Ptolemy's Counus Island, 20th century historians White and Yearsley posit the documented island to have been lost or reduced to an insignificant sandbank by subsidence and the constant effects of the sea. The settlement and agricultural development of