Disappearing Gastropod Mold?

[frozen_turkey]

I was preping this silirian gastropod today (with a electric ingraver) and i was so excited to have a big and whole gastropod that was preserved in certy dolomite. But as i got to the very end i took a flake of the very end and instead of seeing a crystal like mold i just saw a black hole. So i wiped out my ground down dental pick and ciped away a bit of the matrix that was covering the rest of the hole and to my amazment the mold on the right was empty, but the mold seemed to continu on in the hole on the left.

So i was wondering what happened to the rest of the mold????

And for you all that are going to say it just fell out i insure you it didnt.

Here is a pic of it in the feild.

Here it is right after preping and it is still wet from being washed off.

wet

dry

And here is a side shot.

Thanks

-Frozen

[Auspex]

I guess it was either an incomplete shell at burial, or failed to fossilize, or dissolved after the fact.

[Shamalama]

Auspex is correct, I'd say that the original shell was buried with some mud inside but not enough to fill the entire shell. Later the shell dissolved away after the mud had hardened into rock and your left with a half a mold. Just a theory.

[tracer]

the matrix does not look particularly hard, and there is much evidence of acidic groundwater erosion of it. and the holes near where the spire was indicate that area had sufficient porosity to allow more erosion. i believe the spire was there but got dissolved.

[frozen_turkey]

Thanks guys. I was kinda bumbed when i uncovered it. I never found a Silirian gastropod preservered so well. usually all the fossils in cherty dolomite are crushed or poorly preserved.