Lower Horse of islands (five of which later re-clustered to form Canvey Island), that broke away from the English coastline in the medieval period. Lower Horse Lower Horse is a uninhabited island off the English coast, lying in the Thames Estuary between Canvey Island and Stanford-le-Hope, close to . Administratively it is part of Thurrock unitary authority; the border with its ceremonial county namely the administrative county of Essex runs between it and Canvey Island. Smaller than normal markings for an area of saltings (traditional, open air, sea salt extraction through drying) appear in the Ordnance Survey map of 1919, which confirms
Canvey Island the present island, with a ditch being the current boundary, having the same far eastern points as the Canvey Point and Leighbeck Point marshes. Two Tree Island to the north is also recognisable, if halved in length. The third eastern island or mudflat could well be the Counus i.e. "council" Island where the Trinovantes, Cantiaci and the Catuvellauni counselled with the Iceni, shortly before staging Boudicca's rebellion against the Romans. If so Counus occupies an area from the Canvey Point Sand Bank until just before Shoeburyness, the eastern point of the relatively straight estuary so stretched the whole length of