| A tangle of corals from the lower Silurian to lower Devonian Vaughn Gulch Limestone, Inyo County, California; called scientifically Cladopora sp. Specimens are silicified--that is, replaced by the mineral silicon dioxide; reddish-brown coloration derives from the mineral limonite, a variety of hydrated iron oxide. Photograph taken by an individual named Scott Blair, who etched the specimens to such attractive relief on the limestone matrix with dilute acetic acid. I processed the image through photoshop. |