Archaeocyathid?

[Mesoceph]

This is a fossil I am looking at purchasing.  I asked the seller for a better photograph and the photos below were sent to me personally, so I do not believe this is in violation of the terms of the site (though I really do apologize if I have inadvertently broken the rules and I will immediately remove the content!).  I believe the round fossil in the center to be an archaeocyathid, but I would like to be more certain before I pay to have it shipped from southern Australia.  Unfortunately, that is all of the information that the seller has shared with me about location, so I don't have useful information like formation.  I am not certain whether the subdivisions that I am seeing are the result of recrystallization or reflect actual septa.  Thank you for your feedback!

[connorp]

That does look like an Archaeocyathid, and they are known to come from Southern Australia. However, without any further location information, it is impossible to be certain. If you are interested, PM me and I can recommend a US dealer who has much better specimens than the one you have here.