Dendraster Gibbsii - Fossilized Sand Dollar
This specimen is a fossilized sand dollar come from Pliocene Epoch deposits (c. 5,000,000 years old) in the San Joaquin Valley of Central California. It is a remnant of a time when the valley was home to an inland sea seated between the Sierra Nevada Mountains and the California Coast Ranges.
The specimen comes in a classic, glass-topped riker box case measuring 4 x 3 x 1". A small information card is also included. To protect the specimen, we've put each sand dollar in a small bubble wrap bag inside the case.
Sand dollars are echinoderms, an ancient and broad family of animals which includes starfish, sea cucumbers, and sea urchins.
Above: Macro image of radial symmetry with natural stain from petroleum deposits in the San Joaquin Valley.
Like most echinoderms, this species, Dendraster gibbisii, exhibits a five-point radial symmetry which is reflected in the patterns on the surface of the fossil.
Where do they get their color?
The coloring of these specimens is unique among sand dollar fossils due to the presence of petroleum in the San Joaquin Valley deposits which lends a natural stain to the stone.
For an in-depth look at the geology of this region, we recommend stopping by San Joaquin Valley Geology. Their introductory page provides a great overview to the history of the region.
Below are pictures of the preparation process. Each fossil is prepared by hand slowly revealing the patterns beneath the rough exterior and then finishing to a glossy shine.
Please Note: Each specimen is the fossilized remnant of a unique creature and they are all hand-polished. As such, the specimens will vary in size, color, shape, pattern and coloring.