A Crinoid Fossil

Many of the mountains surrounding Helena, Montana, are the upturned remnants of Madison Limestone, a geological treasure formed approximately 330 million years ago during the Mississippian Period. Composed mainly of limestone, this rock formation originated in a shallow sea that covered the region. During the Mississippian Period, Montana was located near the equator and experienced warm, tropical conditions. The limestone layers hold a fascinating array of crinoid fossils, providing insights into ancient marine life.

These creatures are considerably older than the dinosaurs.  Consider, Tyrannosaurus rex, one of the most iconic and fearsome dinosaurs, roamed what is now Montana during the Late Cretaceous Period, approximately 68 to 66 million years ago.

Crinoids, also known as sea lilies or feather stars, were diverse marine organisms resembling flowers on stalks. Flourishing during the Paleozoic Era, they left behind a rich fossil record. The Madison Limestone's fine-grained composition preserved these delicate crinoid fossils exceptionally well.

Yesterday, while kicking around on my property, I picked up a chunk of limestone and found a lovely crinoid fossil embedded within it.

Crinoid Fossil

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—Mitchell Hegman