Any ideas what is in this matrix?

[FreeAngelRN]

Noob here. We tried our luck near Andalusia, but as expected the water was too high. We ended up in Sepulga River and this was all we walked away with, but still curious what might be here. There were lots of new mollusks strewn about and I grabbed these just as a MASSIVE huntsman spider chased me off. 

[Wrangellian]

You definitely have some marine 'hash' there, but would need a clearer pic to tell individual things. Maybe nothing is complete enough to tell more than just "bits of shells".

Try taking some pics in direct sunlight, at varying angles, and don't hold the piece too close to the camera (I take it you're using a cellphone, and I understand these don't focus if the subject is too close. Better to take a clearer shot from further away, and crop the pic if necessary. If you can't crop it, post it anyway and we'll handle it!)

[FreeAngelRN]

Thank you! I'll try your suggestions.