If one pursues that analogy then the Bilsington Monument would qualify as a "seamark". Standing 52 feet (16m) proud on that escarpment it is visible from wherever you are on the Marsh and I think its story is worth the telling.
In 1834 at the age of 51 he fell from his coach in London and died soon after. The Reformers of East Kent, with the support of the people of Bilsington had the monument erected in his memory.
It has had a chequered history, being struck by lightning in 1967 and half destroyed. But a trust was formed and, with Heritage Lottery funding, it was repaired in 1999, ready for the Millenium.
As one gets nearer to the escarpment it accompanies you on the skyline