The following text is from the original listed building designation:
KINGSGATE BAY ROAD 1. 5283 KINGSGATE Remains of Neptune's Temple or 'Arx Ruohim' TR 37 SE 6/121 II
2. Late C18. Another of Lord Holland's follies. This was a miniature built in flint of Henry VIII forts, such as Camber and Deal, and had a central tower of red brick faced with chalk blocks which supported a statue of Neptune. A spurious inscription related that the monument had been built here in AD 448 by King Vortigern - the Arx Ruohim. All that remains now is the flint plinth which is about 10 ft high of quatrefoil shape with a stone band towards the top and arrow slit windows.
Listing NGR: TR3957870547

English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.