4.35" Fossil Pennsylvanian Horsetail (Asterophyllites) Plate - France

Fossil Pennsylvanian Horsetail (Asterophyllites) Plate - France #264530

This is a Pennsylvanian-aged fossil horsetail (Asterophyllites equisetiformis) stalk, collected from Graissessac, France. It measures 4.35" long and is nicely centered on a 5.2 x 2.6" slab of rock. The black fossil stands out nicely against the grey rock.

This is a carbon film fossil, a two dimensional image of an organism. Unlike impression fossils, carbon film fossils show no evidence other than a color change in the rock. All of the original organism has disappeared with the exception of the carbon contained within it. This is deposited on the rock and forms the image we call the fossil. This usually occurs when a soft bodied organism is buried in multiple layers of sediment underwater, and is slowly dissolved until it has disappeared. This leaves only a microscopically thin layer of carbon in the shape of the original organism.

Comes with an acrylic stand.

Asterophyllites is the form genus of leaf clusters of tree-like sphenophytes (horsetails) known as Calamites.

Leaves on Calamites trees formed in clusters of 8 or more, called whorls, at spaced nodes along stems. Asterophyllites leaf clusters curved upward into a sort of cup shape, though the leaves themselves could be any shape. They can also be identified by midline veins throughout the leaf from node to leaf tip.

We use these terms to describe the shapes of fossil imprints. Exact species are often difficult to determine, but these form taxa help in distinguishing the prolific species of sphenophytes that defined the Carboniferous Period.