The earthworks of a large 20th century clay pit can be seen on aerial photographs taken in 1947. The clay pit is to the south-east of Hoo St. Werburgh and was connected via a tramway to brickworks to the south-west (NMR 1545288), an area now occupied by Hoo Marina Park. This clay pit is first depicted on the Ordnance Survey in 1933. To the south was an older clay pit depicted on the 1867 Ordnance Survey map, but presumably disused by that date. Map evidence shows that the northern workings joined those to the south but aerial photographs do not show any evidence that the earlier pit was extended. This clay pit was short lived and was disused by at least 1942 and aerial photographs taken that year show the interior had been brought into arable cultivation. It was mapped from aerial photographs as part of the English Heritage: Hoo Peninsula Landscape Project.