MARTIN LAND / SCIENCE PHOTO LIBRARY MARTIN LAND / SCIENCE PHOTO LIBRARY
Colonies of white fossil graptolites, Didymograptus murchisoni (Beck), on black shale. Graptolites were colonial animals that lived in abundance in Palaeozoic seas. A graptolite colony consists of one or more branches along which are arranged cup-like thecae, each of which originally housed a single animal. The slanting arrangement of the thecae causes the saw-blade appearance of the colony. Members of the genus Didymograptus are called "tuning-fork" graptolites because of their shape. Graptolite means "stone writing" - appropriate because of their resemblance to pencil scribble. Age: Ordovician, 470 million years ago, found in Abereiddy Bay, Dyfed, Wales.
Model release not required. Property release not required.