The remains of 19th and 20th century clay pits can be seen on aerial photographs taken in 1947. These clay pits were situated to the south-west of Hoo St. Werburgh and were associated with the brickworks by the coast to the south of the village (NMR 1545288). The largest clay pit had, by 1947, been incorporated into an arable field and was only visible as a slight depression. This pit was first depicted on the 1909 Ordnance Survey map and apparently disused by 1933 although the earthworks define larger area than that marked on the map, suggesting that the clay pit was brought back into use after 1933. To the south was a smaller but, in 1947, still opened clay pit (but since incorporated int an arable field). Although approximately at the location of an 1896 clay pit (abandoned 1909) this may represent later extraction. This earlier clay pit was connected to the brick works by a tramway. When this was abandoned the line was redirected to the larger clay pit to the north. Remains of the tramway are recorded in NMR xxxxxxx). . These earthworks were mapped from aerial photographs as part of the English Heritage: Hoo Peninsula Landscape Project.