The aragnite shells of snails don't preserve in Fossil Lake. In some layers the shell is indicated by a limonite-colored stain (4ed22e93-3238-437d-bc79-4cd3a72839bc)

A yellow-brown snail fossil on tan stone. The top of the snail is on the left and the thicker bottom is on the right.
The aragnite shells of snails don't preserve in Fossil Lake. In some layers the shell is indicated by a limonite-colored stain. This specimen is not currently on display. Catalog number FOBU9678.