Specimens of graptolites in shale from Abereiddy Bay, Wales, these samples have been dated to the Ordovician period. This shale contains the small, delicate, blade-like fossils of colonial marine creatures known as Graptolites. (phylum Hemichordata). They are known chiefly from the Upper Cambrian through the Lower Carboniferous Their name is derived from Greek graptos & lithos, which roughly translates as "written on rock" as they do have the appearance of being pencil drawn. Their structure is best viewed with a hand lens. Graptolites are globally wide ranging so are used as index fossils. Specimens are supplied in a 2" x 2" white card tray with an information label.