Trilobite

I've picked up several rocks along Lake Michigan with fossil shapes of this form, arcs segmented down the middle by closely set, nearly parallel lines. This hunk of iron-stained limestone contains one of the largest and most distinct impressions. Trilobites molted, shed their exoskeletons to inhabit larger ones. I believe these shapes and the others … Continue reading Trilobite

Trilobite

This is a mold fossil of a trilobite captured in chert-y sandstone. Though local bedrock is Devonian dolomite and limestone, glaciers brought rocks from north of here and deposited them all over this part of Wisconsin. This trilobite could have come from as far away as Canada. A poetry exists in the ghosts encased in … Continue reading Trilobite

Trilobites

The Precambrian Eon spans geologic time from the formation of Earth about 4.6 billion years ago to about 541 million years ago. That's roughly 90 percent of Earth's lifetime so far. The Paleozoic Era followed, beginning with the Cambrian Period. No leap of logic, that. One way to view Earth's timeline is to think of … Continue reading Trilobites