Tuesday, 17 February 2015

Trilobites and their eyes

Trilobites are found as fossils in Palaeozoic rocks - aged from around 540 million years to around 250 million years.

They were given the name because they have three parts to their bodies.

There are many types of trilobites but they all have the same basic structure.

The cephalon (head) contains two amazing eyes.

The eyes are made of many lenses, each lens is a crystal of calcite - calcium carbonate.

One problem with calcite crystals is that if looked through in some directions, they split light to make two pictures.

Trilobite eyes have the crystals lined up in the one direction to avoid that problem.

Trilobite biscuits make an unusual idea for a kid who likes fossils.

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