Blastoidea is an extinct type of echinoderms. Originating in the Ordovician Period, 485—444 million years ago, along with many other echinoderm classes, they reached their greatest diversity in the Mississippian, or early Carboniferous, and persisted until the great extinction at the end of Permian. The concrete stamping tool has an overall size of 14” x 24” ( 35.5 x 61 cm.) with a medium slate texture.
Item # 9F27