A group of possible 20th century circular depressions are visible on aerial photographs taken in 1947 and 1952. These were situated north of Hoo Marsh at TQ 8072 7725. They consisted of seven circular depressions that measured between 6m-7m in diameter. These are filled with water in 1947 but in 1952 the interiors of 6 of these can be seen. They are defined by an outer ditch encloses a circular bank with a central depression. One of these was dug in to an old sea wall. Within this area were also a group of 14 closely spaced circular depressions circa 1.5m in diameter. All these depressions occupied an area defined by drainage ditches to the west and a railway embankment (NMR 1547406) to the east suggesting that they were formed after this early 20th century railway line was built. This area is now beneath Kingsnorth power station. They were possibly associated with the RNAS station nearby (1458978) and they were mapped as part of the English Heritage: Hoo Peninsula Project.(1-2)

Archive: MD003097 Hoo Peninsula Landscape Project: TQ 87 SW Material still held by Aerial Survey.

<1> RAF, 1947, RAF CPE/UK/1923 4090-4091 16-JAN-1947 (Photograph). SKE55930.

<2> RAF, 1952, RAF 58/856 4139-4140 24-APR-1952 (Photograph). SKE56100.