Mined from: Osgood Shale, Napoleon Indiana

Era: Silurian
Geological Age: Approximately 430 to 428 mya

Description: Step back over 420 million years with this rare specimen of Holocystites scutellatus silurian, an extinct marine organism belonging to the cystoid class of echinoderms. Cystoids are close relatives of modern crinoids and sea urchins but had their own distinctive, often geometric body structures. This fossilized specimen, originating from Silurian-aged deposits, captures the unique textured plates and globular shape that defined these fascinating early sea creatures. Each fossil is a relic of a long-vanished ecosystem, offering a glimpse into Earth's dynamic evolutionary history.

The Silurian Period (approximately 443–419 million years ago) was a critical time in the development of complex marine life. Oceans teemed with new forms of coral, jawless fish, and various shelled organisms, and cystoids like Holocystites scutellatus occupied shallow seabeds. Their robust, calcite-based exoskeletons allowed them to fossilize beautifully, with many specimens still displaying detailed plate sutures and the subtle ornamentation of their theca (main body). Fossils of this quality are highly sought after by collectors, educators, and museums alike for their rarity and scientific importance.

Approximate Size of 1 piece: 3cm x 2cm x 1cm
Approximate Weight of 1 piece: 10g

Approximate Size of 1 piece: 3.5cm x 2.5cm x 1.5cm
Approximate Weight of 1 piece: 20g

Approximate Size of 1 piece: 4cm x 3cm x 1.5cm
Approximate Weight of 1 piece: 30g

Quantity: 1pc

We do our best to buy quality products- although not every rock is the same. If you choose to purchase the "staff pick option", we will select the best of the batch for you. Otherwise, it will be at random from the larger batch we have in stock.