Only rock identification is off-topic.
Please vote to reopen this question.
Though I'm not a frequent user here, from what I remember of the rock ID issue this kind of question isn't likely to cause the same kinds of issues or concerns. I don't see any benefit to the site from keeping this question closed and blocking people from posting answers.
Voting to reopen!
I think the issue with the post isn't that it's off-topic per se. However, the quality of the post is basically a "here is a picture I took; What is it?", which leads to opinion-based answers with no way to confirm/deny them. These type of posts need more investment from the OP to ask a quality question about fossils in order for them to be of value to the greater ES community. Most importantly, the poster needs to research the question they are interested in before asking the question, perhaps providing references or links to other samples they've found.