Dimensions: 18in. X 4 in.

This flattened fossil cast of the Sigillaria tree was found in the roof of an underground coal mine-- lodged in the base of a small sandstone channel that marks the boundary of a meandering stream that flowed 300+ million years ago along an ancient delta that existed then.

Sigillaria is characterized by a fluted bark pattern comprised of parallel grooves running longitudinally up and down the trunk.

On small specimens it can resemble certain species of Calamites, but can be easily differentiated because Sigillaria does not have any horizontal girdles of rib nodes that are common to all Calamites. Likewise, Calamites does not have any vertically aligned leaf scars-- a trademark of Sigillaria.

An expanded view. of the lower central portion of this specimen illustrates the alignment of leaf scars in these structures. A leaflet was attached at each one in life. The black crust is a thin layer of coal.

On the reverse side of this specimen is a similar fluted pattern with leaf scars.

When you see such a combination of fluted pattern and vetically-aligned leaf scars, together, you can be sure you are looking at Sigillaria.

 

Rock Type: Gray sandy shale
Formation: Allegheny
Interval: 5-Block (Lower Kittanning) seam
Age: Middle Pennsylvanian Period, approx. 304 million years.

Location: Preston County, West Virginia; Whitetail K-Mine No.1, operated by Kingwood Mining Company, located about 1.5 miles north of Fellowsville, West Virginia. Collecting by the public is generally not available here.