Didymograptus graptolite fossils

Didymograptus graptolite fossil specimens

Specimens of the graptolite Didymograptus murchisoni, found around Abereiddy Bay, Pembrokeshire, Wales.

These Graptolites date to the Middle Ordovician, about 470 to 464 million years ago. They are comprised of a soft shale, and have been sealed with a varnish to protect the top surface.

They are a widely used index fossil, and always remind me of saw blades!