Category
page 1Ordovician Canada
Lunataspis
Lunataspis is the oldest known xiphosuran, with three known species all dating from the late Ordovician (latest Sandbian for L. borealis, Katian for L. gundersoni, earliest Hirnantian for L. aurora).
Onnia
genus of trilobites
Didymograptus
Didymograptus is an extinct genus of graptolites with four rows of cups. They lived during the Middle Ordovician, to Late Ordovician.
Ordovician meteor event
event of around 467 million years ago
Tetragraptus
Tetragraptus is an extinct genus of graptolites from the Ordovician period.