One thing that will have thrown the author off the trail is that he is holding a fossil of the organic parts of the snail and that is essentially a cast of the animal, not the shell. They are known as Steinkerns (stonecore).

The insides get replaced by minerals, which harden, the shell dissolves, then the only fossil remaining is a mould of the inside of what used to be the shell.

So on a fundamental level, the headline is wrong. He did not find any sort of shell...

I've been told by a friend -- a wierd thing -- in many places you can dig a hole and it will fill with water. And at some point in the future fish will be swimming in it.

Or trilobites?

with a "pond sized" hole, I have read that fish eggs arrive on the feet of ducks and other waterfowl attracted to the new pond. (I have never looked up whether this is a myth)

Splitting hairs in bad faith is not constructive to the points being made here.

True, but I actually had no idea that it was the soft parts rather than the hard parts that had been fossilized. (I haven’t verified it yet.) Either way, it didn’t read like a bad faith interpretation/comment.

It wasn't written to be one. If the author went to the trouble of making a 3D space filled with many shells, knowing the actual shell was most likely a different shape would be something they would probably want to know, so the position of their fossil could be placed more accurately in the graphed space.

No, a layperson doing a bunch of math but barking up the wrong tree theory-wise is actually super instructive for this forum of autodidacts.

And I say that as one of the autodidacts.

Reads to me like a fascinating and relevant distinction.

how is that splitting hairs? it’s an actual interesting point