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
Severn Estuary the line between Lavernock Point and Sand Point is the Bristol Channel, which in turn discharges into the Celtic Sea and the wider Atlantic Ocean. The islands of Steep Holm and Flat Holm are located close to that line, in the middle of the estuary. Sometimes the term "Severn Estuary" is used to include the tidal upstream stretch between Gloucester and Aust. During the highest tides on the upper reaches of this stretch, the rising water is funnelled up the estuary into the Severn bore, a self-reinforcing solitary wave that travels rapidly upstream against the river current. The tidal range