Mellita caroliniana inside a Dinocardium robustum

Mellita caroliniana inside of a Dinocardium robustum
Waccamaw Formation
Early Pleistocene (~2.5 Ma)
Columbus County, North Carolina, USA

Self collected in November, 2023

This is my first "whole" echinoid of the Waccamaw formation, and my third North Carolina species found! This Mellita caroliniana was hiding inside of a matrix-filled Dinocardium robustum also known as the Atlantic Giant Cockle. I discovered it at the last moment before I probably would have accidentally destroyed it, though I was using a less aggressive cleaning method due to a drought in the area. There are a number of other mollusk species in the cockle as well, but I stopped attempting to extract them to keep the matrix stable.

The aboral surface is crushed in and the petaloids are a little fractured due to this, with some very small surface pieces missing, but it is still a great specimen! It is currently sitting in a cabinet until I can figure out the best way to preserve it with consolidant, as I am worried it will fall apart if I am not careful. It is likely going to stay in this cockle as well, which I think makes for a good pairing, as well as a demonstration as to how things get buried together in the formation.

There is another fragmented specimen in the shell as well, but likely not complete. There is no telling what else is buried in the matrix beneath the sand dollar that I may never unearth; there could be a whole other echinoid under there as far as I know!