Ellenburger Limestone (cut as for building stone) Location: listed as East of Helotes County: Bexar County Chemical Formula: CaCO3 Specimen Size: 4.75 x 3.75 x 1.5 inches Specimen Weight: 805 grams In the Jackson School Collection, at the University of Texas at Austin. Collection Reference: TMM 565
Iron Ore (highly magnetic) Location: Iron Mountain (at 30°51' N, 98°54' W). County: Llano County Chemical Formula: Fe(2+) Fe2 (3+) O4 Crystal System: Isometric Specimen Size: 3.5 x 1.25 x 2 inches Specimen weight: 602 grams In the Jackson School Collection at the University of Texas at Austin. Collection Reference: TMM 1509 Additional Information: Smoothing Iron Mountain, also known as Iron Mountain, stands four miles west of the town of Valley Spring in northwestern Llano County (at 30°51' N, 98°54' W). It is the location of perhaps the largest iron ore deposit in the state. Although not the foundation for a significant Texas iron industry that some promoters had anticipated, this deposit has been mined several times, most recently in the 1930s. At an elevation of 1,839 feet, the mountain rises approximately 520 feet above nearby Cold Creek.
Cross Section of petrified Palmwood (Palmoxylon), without scale. This specimen is 6" wide by 5" tall. 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.
