| This is a "wishbone-shaped" graptolite called scientifically, Didymograptus protobifidus. The Lower Ordovician Al Rose Formation is one of California's premiere early Ordovician graptolite-bearing geologic formation. Many of the graptolite remains, including the specimen shown here, have been replaced by the mineral limonite, giving the extinct hemichordates a distinctive "golden" glow, which contrasts nicely with the dark-greenish shales upon which they have been preserved. Collected from Inyo County, California. |