Hi OP, I thought would be a great question for the newly created Geology group, so I posted a link to it there and got this great answer – in short:
There are many small fossils on that rock. It would be hard to tell what the rock itself is from just the photo. Limestone is the most likely candidate.
Go and read the full answer for more details!
If you’re happy with the answers you’ve got could you edit your title to add [SOLVED] at the end? Thanks, Michael
Thank you, much appreciated!
Could you edit your title to add [SOLVED]
Yeah. Looks like some sedimentary rock that has a few shells fossilized. If I had to bet, the rock itself is limestone perhaps?
Is that something that forms in a short period of time, or is this a prehistoric formation, do you think? Those shells don’t seem ancient, but what do I know, these shells probably have had the same shape for millions of years.
Oh man, I am not the guy to ask that haha, just using some preliminary knowledge. According to the Fossil wikipedia though, a fossil is considered such if it is older than 10,000 years. What we’re looking at is apparently called an external mold, where something embeds a mold of itself into a rock. I haven’t been able to find any info regarding how long these things take to form, but most examples I see are tens of thousands of years old.
So I would guess that rock/mold is thousands of years old then. But you’re right, it could definitely be millions if you got lucky.
That’s fascinating! I didn’t know external mold was a thing, although it makes sense. Thanks for the information
