The Great Beatty Mudmound Fossils

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The Great Beatty Mudmound: This bioherm was first recognized in 1960 by geologists H.R. Cornwell and F.G. Kleinhampl during their geological mapping of the region. This pod-shaped accumulation of calcium carbonate is some 270 feet thick and more than 1,000 feet in length as it protrudes from the west side of a mountain above Secret Pass just south of Meiklejohn Peak, elevation 5,940 feet. To gain a better appreciation of the mudmound's dimensions, one must hike up a steep canyon wash and stand near the base of it. From this up-close-and-personal vantage point, this uncommon geological structure is a massive, pale gray body of limestone exposed along the skyline of the mountains, that truly dominates the view. It was much bigger than we expected. Written reports on the Internet indicate that the core of this formation contains a wealth of excellently preserved invertebrate animal remains some 480 million years old, including echinoderms, sponges, bryozoans, ostracodes (tiny bivalve crustaceans related to barnacles), pelecypods, gastropods, trilobites, conodonts, cephalopods and brachiopods. The specimens are restricted to sporadic, productive pockets within the core of the mudmound and to, more abundantly, the medium gray to olive-gray and olive-brown shaley limestones along its flanks and directly above the mudmound itself. other calcium carbonate layers contain prolific quantities of brachiopods, most of which are rather tiny.