I found this in an old quarry at the foot of the Old Man of Coniston, Cumbria, England about 30 years back. It's from the Ashgill Shales, so is very uppermost Hirnantian, Upper Ordovician.
It was a dome shape but broke during extraction,to reveal a smaller dome within the dome and so on, but is built up of layers and layers though the 'tubes' running through it also continue upwards and outwards from the base. Is it Fisherites ? It's about 3.5 cm in diameter but was a little bit bigger.
Thanks for any help.
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