Lepidodendron (scale trees): Link to great blog post on these Carboniferous giants

At the time of this writing, the wallpaper of my blog is a snapshot of Lepidodendron bark. Lepidodendron is an extinct genus of Carboniferous age (358.9-298.9 million years ago [Ma]) giant trees (AKA scale trees) common in swamps that eventually were preserved as major coal deposits. Its stylized bark is quite artistically attractive, rather Art Deco in design.

Yesterday I read a great informative blog post on Lepidodendron (http://www.indefenseofplants.com/blog/2018/11/13/the-rise-and-fall-of-the-scale-trees), describing the growth, reproduction, habitat, and demise of these majestic (100 foot/ 30 meter) land plants. The post includes origin of the bark design:

“The name ‘scale tree’ stems from the fossilized remains of their bark, which resembles reptile skin more than it does anything botanical. Fossilized trunk and stem casts are adorned with diamond shaped impressions arranged in rows of ascending spirals. These are not scales, of course, but rather they are leaf scars. In life, scale trees were adorned with long, needle-like leaves, each with a single vein for plumbing. Before they started branching, young trees would have resembled a bushy, green bottle brush.”

That blog post also includes a very sharp photo of Lepidodendron bark, the roots with their own fascinating pattern (stigmaria), and drawings of Lepidodendron species, growth stages, and forest environment.

Below are two photos I took of Lepidodendron for my blog wallpaper. The sample is in the mineralogy collection of the Department of Geology and Environmental Geosciences, Lafayette College, Easton, Pennsylvania. The sample is from the Llewellyn Formation, the younger of two Pennsylvanian-age coal-bearing formations (older= Pottsville Formation) in the eastern Pennsylvania anthracite coalfields. The Pennsylvanian subsystem (323.2-298.9Ma) is the term for the late Carboniferous in North America. The Llewellyn itself was deposited between 308-300 Ma. The Llewellyn Formation also contains the famous St. Clair fossil fern locality. 

For an academic, rather than chatty, description of the St. Clair fossil locality (plus anthracite region mining, stratigraphy, fossils), I recommend two guidebooks: 1) 2015 guidebook to the Southern and Western Anthracite Fields by the Field Conference of Pennsylvania Geologists; Stop 12, page 237, is the St. Clair fossil site; 2) 1992 The Society for Organic Petrology (TSOP) guidebook to The Anthracite Basins of Eastern Pennsylvania (USGS Open File Report #92-568; (https://pubs.usgs.gov/of/1992/0568/report.pdf)); the St. Clair locality is Stop 5, page 65. Both guidebooks include references to Lepidodendron throughout.