Can anyone help identify this unusual rock I found in the stones on my driveway thankyou
Yes, OK, definitely rock; and definitely fossil.
I don't think it is a cast, nor an internal mould; it is a proper fossil.
But it sets no bells ringing. I don't think it is coral, probably not bryozoan or echinoid or plant seed.
I hope somebody else has some inspiration!
Don't know what it is Mike, but I think it's got the base of an Echinoid and the structure of a colonial corral.
So is it a Sponge?????
I think the specimen has all of the characteristics of the specimens mentioned.
I think you are right, thanks.
The structure/texture seen on the sides was putting me off, being rather irregular. But it is actually quite like some Ventriculites, as in this fine example - http://www.nhm.ac.uk/resources-rx/images/1010/sponge-047598-340_100766_1.jpg
...Though most Ventriculites have a more-regular structure, as seen here
The overall structure of Ventriculites is wrong, however.
The 'basal/apical disc' and radiating lines are similar to ones seen here:
- http://www.oum.ox.ac.uk/thezone/fossils/inverts/sponge.htm (near bottom-right of image)
Astylospongia (re the preceding two links) is probably too old, but maybe another genus in the
The NHM has a good collection of sponges (over 70,000 specimens)
Unfortunately, it is not available online.