What is a Fossil?
continued from main newsletter

Most of Texas was underwater at one time and the oysters, snails, clams and other life in the ocean were trapped in the silt as the waters receded. Over the years these items turned to stone to make the fossils we see today.

Some of the shells themselves have survived in a fossilized form. Some of what we find are “cast” fossils, meaning that the shell made an impression in the silt as it was hardening and we can still see the outline. Some are “mold” fossils, that means that the silt that settled into the shells hardened into stone and the shell broke off from around the resulting “mold”.