Found at North Myrtle Beach

[MeganSever]

Hey everyone! I found this interesting piece of seashell at North Myrtle Beach almost a month ago and I still can’t figure it out! I’ve been trying to scratch it but can’t because it’s really hard and the things I’ve been scratching it with (seashell, coin, etc.) has been coming off onto the mysterious object. It was found in between the afternoon so like 1-2 pm and it was at North Myrtle Beach . Can anyone help me? 

[Thomas.Dodson]

It could be a piece of limestone or perhaps a bryozoan. I can't tell with the pictures but look for small cells/holes (Zooecia) in the surface of the object. If you can get an in-focus close-up picture of the object (straight on picture, non-oblique angle) in good lighting we might be able to see as well.

[fossilnut]

The shape certainly makes one think of a bryozoan as Thomas.Dodson suggests look for small cells/holes. It could also possibly be a cast of a small burrow?

[CrazyRockLady]

It also could be a sponge. It resembles the Doryderma genus to me.