| An overview of the middle Cambrian Wheeler Shale at Wheeler Amphitheater (AKA, Antelope Springs), western Millard County, Utah, a number of miles east of the eastern border of White Pine County, Nevada. All the graysish to tan-colored rocks in roughly middlegrould of photograph belongs to the Wheeler Shale, which yields a fantastic diversity of middle Cambrian fossil material: 35 species of trilobites; brachiopods; echinoderms, including an eocrinoid ("dawn crinoid") called Gogia; Phyllocarids (a bivalve crustacean with only two known living members)--including the extinct Brachiocaris and Pseudoarctolepsis; such early siliceous sponges as Diagonella, Choia, and Chancelloria; an early Chelicerate (horseshoe crabs, sea spiders, and arachnids are living members) called Esmeraldella; Naraoia, a so-called trilobitomorpha, or "soft-bodied trilobite;" Anomalocaris, the largest predator of the Cambrian seas; annelids (the worms), including famous Wiwaxia, which was first described from the astounding middle Cambrian Burgess Shale of Canada; and 20 species of non-mineralized arthropods unrelated to trilobites--in other words, soft-bodied animal remains rarely encountered in the fossil record. Photograph courtesy Paololitico F/Panoramio; I edited and processed the image through photoshop. |