So-called Sussex ‘Marble’ is also known as winklestone, Paludina limestone, Bethersden Marble, Charlwood Stone, Laughton Marble, and Petworth Marble. But whatever it’s called, its defining characteristic is the particular type of fossil snail whose sectioned shell gives the stone its unique character: the freshwater gastropod Paludina (now known as Viviparus). In the past, other shelly limestones, especailly those containing the bivalve Cyrena, were probably passed off as Sussex Marble.
To claim that ‘Sussex Marble’ is a marble isn’t right –
It’s a limestone in the beds of old Weald Clay.
But it takes a lovely polish, so it shines up nice and bright
Once you’ve dug it up and carted it away .
And polishing reveals its ancient snail-encrusted core,
A challenge for the Latin-name-assigner.
They came from boggy places, these old fossil shells of yore,
So from palus (meaning marsh) came Paludina*.
(Beware of ‘Sussex Marble’ though, with bivalves peeping through –
Not a single sectioned snail-shell to be seen.
It isn’t Sussex Marble with its Paludina crew,
These bivalves are Cyrena – ‘sovereign queen’.)
*The pronunciation of this word was a puzzle (I had a Latin-free education). Sources at two learned institutions admitted they didn’t know, but an on-line pronunciation aid for biological terms seemed to suggest a long, stressed penultimate vowel: Pal-u-DYE-na.