Abbey River Tideway where there are two larger islands. It is much smaller than Canvey Island and the Isle of Sheppey and narrowly ahead of Andersey Island facing Abingdon-on-Thames, another market town with an abbey which had multiple medieval mills, another of note being Westminster Abbey, the island of which Thorney Island no longer exists. The outfall of the Abbey River is 400 m above Chertsey Bridge, into the weir pool of Chertsey Weir. The manmade strictly-considered "island" the bypass channel forms is outranked in size since the 2002 completion of the Jubilee River by the example containing Dorney and Eton, Berkshire.
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