Brachiopods spiced with trilobites are the main ingredients of this Devonian fossil hash. Trilobites, though now extinct, are relatives of living invertebrate animals such as crabs and insects. Brachiopods have two shells, rather like clams. You are looking at various cuts through the animals' shells. Notice the delicate, curving growth lines that are preserved in some of the brachiopod shells. When the animals died and the flesh rotted away, great numbers of shells were left behind. Waves sorted the shells out from the sand and mud, and stacked them like shingles, each one overlapping the next. Later calcite grew in the spaces, cementing the hash together.

Plane polarized light