A new crinoid association reported from the Kope Formation (Katian, Ordovician) of northern Kentucky and southwestern Ohio changes the model for facies distribution of crinoids along an Ordovician ...

The pebbles are prettier on the other side of Lake Michigan. Even amateur beachcombers know that the Dunes-area shoreline of Indiana and Michigan yields better rocks than Chicago’s gravelly man-made ...

Two new Early Ordovician crinoids have been discovered in Gondwanan rocks of northwest Argentina. Ramseyocrìnus argentinus n. sp., among the most complete for the genus, aids in reconstructing key ...

Marine fossil specimens unearthed in northern Portugal are filling a gap in understanding evolution during the Middle Ordovician period. A clutch of marine fossil specimens unearthed in northern ...

The Earth has gone through many major events over the course of hundreds of millions of years. Some of the most significant are the six mass extinction events that have occurred. These are times when ...

Paleontologists recognize five big mass extinctions in the fossil record. At the end of the Ordovician period, about 443 million years ago, an estimated 86 percent of all marine species disappeared.

One of Earth's most consequential bursts of biodiversity—a 30-million-year period of explosive evolutionary changes spawning innumerable new species—may have the most modest of creatures to thank for ...