All fossils are welcome!
Fossilized Sand Dollars
What is a sanddollar? It is a flat, disc-shaped sea urchin that is also related to starfish. A living sand dollar is covered in thousands of fur-like spines that allow it to locomote and burrow into the sand. Sand dollars feed through a central orifice on their flat bottom and they excrete waste through a smaller orifice near the edge of their body. They breathe through fine mesh structures that are located on top of the hollow shell and that are arranged in a pattern that resembles a flower with 5 petals. San dollars do not have a brain. but a nerve ring. They live in colonies of hundreds of individuals and are close to being endangered. The largest species reaches a diameter of about 5 inches. Sand dollars wash up on beaches after storms and when the tides are extreme. When a sand dollar dies after about 6 years its shell is left behind. The shell contains five loose jaws that because of their bird-like appearance are commonly called peace doves.
Fossilized sand dollars can wash up on the shore. In the Bay Area, they are most commonly legally found and collected after being washed out of the Merced Layer, a strata that is exposed in a bluff that runs for several miles along the coast between Daily City and San Francisco. After winter storms pound the bluff face, you can find dozens of fossilized sand dollars on the beach. Collecting in other areas is mostly prohibited. There is another area in Santa Cruz where you can find fossilized sand dollars and other fossils, including ammonites and fossilized shark teeth. Fossilization takes thousands of years, probably upward of 10,000 tears, and sand dollars are ancient creatures, having existed since the Paleocene 65 million years ago.
When my son was young we often looked and found fossilized sand dollars. We took the rocks home, split them open, ground away the rock, and polished the fossils. I understand reading this was a bit of a slog but while a picture says a thousand words a picture without words can be quite insufficient. On to the pictures!
Just to jog everyone's memory: Here are a few sanddollar shells. One is flipped upside down.
This is one of the five jaws, a so-called peace dove. Many people collect them.
This is a nodule that I recently found on the beach. It contains a fossilized sand dollar. I can tell because of the white inclusion that gives the pebble the appearance of an Oreo cookie. The sea has tumbled the nodule over who-knows-how-long and has exposed the edges of the fossil within.
This is a nodule that I began grinding. I put some water on it so that the fossil becomes more obvious. When not wet it looks just like near-featureless grey rock.
This is a san dollar me an my son ground and polished about twen years ago. It's the best fossilized specimen we have.
Here is another partial sand dollar fossil. There are two in there, back-to-back!
Fossilized Sand Dollars
What is a sanddollar? It is a flat, disc-shaped sea urchin that is also related to starfish. A living sand dollar is covered in thousands of fur-like spines that allow it to locomote and burrow into the sand. Sand dollars feed through a central orifice on their flat bottom and they excrete waste through a smaller orifice near the edge of their body. They breathe through fine mesh structures that are located on top of the hollow shell and that are arranged in a pattern that resembles a flower with 5 petals. San dollars do not have a brain. but a nerve ring. They live in colonies of hundreds of individuals and are close to being endangered. The largest species reaches a diameter of about 5 inches. Sand dollars wash up on beaches after storms and when the tides are extreme. When a sand dollar dies after about 6 years its shell is left behind. The shell contains five loose jaws that because of their bird-like appearance are commonly called peace doves.
Fossilized sand dollars can wash up on the shore. In the Bay Area, they are most commonly legally found and collected after being washed out of the Merced Layer, a strata that is exposed in a bluff that runs for several miles along the coast between Daily City and San Francisco. After winter storms pound the bluff face, you can find dozens of fossilized sand dollars on the beach. Collecting in other areas is mostly prohibited. There is another area in Santa Cruz where you can find fossilized sand dollars and other fossils, including ammonites and fossilized shark teeth. Fossilization takes thousands of years, probably upward of 10,000 tears, and sand dollars are ancient creatures, having existed since the Paleocene 65 million years ago.
When my son was young we often looked and found fossilized sand dollars. We took the rocks home, split them open, ground away the rock, and polished the fossils. I understand reading this was a bit of a slog but while a picture says a thousand words a picture without words can be quite insufficient. On to the pictures!
Just to jog everyone's memory: Here are a few sanddollar shells. One is flipped upside down.
This is one of the five jaws, a so-called peace dove. Many people collect them.
This is a nodule that I recently found on the beach. It contains a fossilized sand dollar. I can tell because of the white inclusion that gives the pebble the appearance of an Oreo cookie. The sea has tumbled the nodule over who-knows-how-long and has exposed the edges of the fossil within.
This is a nodule that I began grinding. I put some water on it so that the fossil becomes more obvious. When not wet it looks just like near-featureless grey rock.
This is a san dollar me an my son ground and polished about twen years ago. It's the best fossilized specimen we have.
Here is another partial sand dollar fossil. There are two in there, back-to-back!
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