Kasia has returned to grace the blog with treasures from her Abaco beach-combing from the Delphi Club and further afield. Expect more shells, more sea glass… and more mystery objects. We have already had part of a RAY’S PALATE and a PACIFIC ANGARIA SHELL  that had somehow arrived on the shores of Abaco. There’s a long thin WHITE BONE, as yet unidentified (no suggestions yet). And now this extraordinary item… 

To which my answer is “not the faintest idea”. My guesses are (1) a fossilised vertebra of some medium-sized creature (2) a fossilised ‘soft’ rock that worms have been at (but why only on one side?) (3) a bread roll that went disastrously wrong in the baking…

All suggestions welcome, preferably via the COMMENT box (so others can view them); or to rollingharbour.delphiATgmail.com (spam guard: convert AT to @)

STOP PRESS Mystery quickly solved, thanks to Colin Redfern who says “This is part of the remains of a colony of Petaloconchus worm-shells (molluscs). They attach to rock or coral, and the colonies can be quite large.”  Colin’s website includes some examples from his archive, one chunk being very similar to Kasia’s 

And here’s another chunk, top and bottom view Photos courtesy of James St. John (Geology, Ohio State University at Newark)
…and here is the worm that makes the vermi-accretion or whatever the term is