Petrified Palmwood (Palmoxylon), probably Sabine County, Texas
Cross Section of petrified Palmwood (Palmoxylon), with penny for scale. This specimen is 6" wide by 5" tall. Texas designated petrified palmwood as the official state "stone" in 1969 (but petrified wood is technically a fossil, not a stone).
Specimens from the Oligocene epoch (34 - 23 mya) can be collected from many scattered sites in east Texas and western Louisiana. Fossils found near fossil palmwood include corals, sponges, and mollusks, indicating that the palms grew along prehistoric beaches. For millions of years, the Gulf Coast shoreline has been moving farther south.
Petrified palmwood includes a group of fossil woods that contain prominent rod-like structures within the regular grain of the silicified wood. Depending upon the angle at which they are cut by fracture, these rod-like structures show up as spots, tapering rods, or continuous lines. The rod-like structures are sclerenchyma bundles that comprise part of the woody tissues that gave the wood its vertical strength.
This specimen was donated by the Morris family to the Bureau of Economic Geology at the University of Texas at Austin.