Calamites fossil wood in sandstone in the Pennsylvanian of Ohio, USA.

This is float from the lowermost Pottsville Group, a Pennsylvanian-aged, cyclothemic succession in eastern Ohio that contains nonmarine shales, marine shales, siltstones, sandstones, coals, marine limestones, and chert ("flint"). The lower Pottsville dates to the late Early Pennsylvanian. The upper part dates to the early Middle Pennsylvanian. The Lower-Middle Pennsylvanian boundary is apparently somewhere near the Boggs Member (?).

At this site, the basal Pottsville is a spectacular quartz-pebble conglomerate, with a quartzose sandstone unit above it, plus coal, sandstone, and shale above that.

In eastern and northeastern Ohio, the conglomeratic base of the Pottsville Group is called the Sharon Conglomerate (a.k.a. Sharon Sandstone; Sharon Formation; Sharon Member). The literature points out that the Sharon elsewhere in Ohio is not directly correlatable with the conglomerate exposed at this site near Jackson, Ohio. Thus, it has been suggested that the unit at this locality be referred to as the "Sharon" Conglomerate.

The fossil plant shown here is in quartzose sandstone derived from the "Sharon" Conglomerate (or possibly a separate sandstone body near the top of the outcrop). The fossil is identifiable as Calamites, a relatively common sphenophyte in Pennsylvanian nonmarine rocks. Calamites is a fossil calamitacean sphenophyte, a group of plants that has only one living genus - Equisetum (= horsetails/scouring rushes). Sphenophytes are readily recognized - they have a central axis (stem) with whorls of leaves originating from widely-spaced nodes (e.g., see: <a href="https://www.flickr.com/photos/jsjgeology/15344675408">www.flickr.com/photos/jsjgeology/15344675408</a>).

Classification: Plantae, Sphenophyta, Equisetales, Calamitaceae

Stratigraphy: float from the "Sharon" Conglomerate, or possibly from an overlying sandstone unit, lowermost Pottsville Group, Lower Pennsylvanian

Locality: Jackson North Outcrop - roadcut along the southwestern side of Rt. 35, immediately southeast of the Rt. 35-Lloyds Bridge Road intersection (the northwestern intersection - there are two of them), north of the town of Jackson, northwest-central Jackson County, southern Ohio, USA (39° 06’ 32.94” North latitude, 82° 40’ 39.99” West longitude)

See info. at: <a href="https://en.wikipedia.org/wiki/Calamites" rel="nofollow">en.wikipedia.org/wiki/Calamites</a> and