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Ammonites from the upper part of the Pierre Shale and Fox Hills Formation of Colorado. American Museum novitates ; no. 3388

Show simple item record Landman, Neil H. en_US Cobban, William A., 1916-2015. en_US 2005-10-06T16:41:29Z 2005-10-06T16:41:29Z 2003 en_US
dc.description 45 p. : ill., maps ; 26 cm. en_US
dc.description Includes bibliographical references (p. 42-44). en_US
dc.description.abstract The upper part of the Pierre Shale and Fox Hills Formation were deposited in the late Cretaceous (Maastrichtian) Western Interior Seaway. They crop out in a belt that roughly parallels the Front Range of the Rocky Mountains from Douglas to Weld County, Colorado. These rocks consist of sandy shales and sandstones and are overlain by the nonmarine Laramie Formation. A sparse assemblage of ammonites is present consisting of Coahuilites sheltoni Böse, 1928, Sphenodiscus pleurisepta (Conrad, 1857), Trachybaculites sp. cf. T. columna (Morton, 1834), Hoploscaphites birkelundae Landman and Waage, 1993, Hoploscaphites sp. cf. H. birkelundae, Jeletzkytes dorfi Landman and Waage, 1993, and Jeletzkytes sp. cf. J. dorfi. Hoploscaphites birkelundae and Jeletzkytes dorfi define the H. birkelundae Zone in the Western Interior, which represents the lower part of the Upper Maastrichtian. These rocks are thus equivalent in age to the Fox Hills Formation in Niobrara County, Wyoming, and older than the type Fox Hills Formation in north-central South Dakota. An analysis of the ratio of ⁸⁷Sr/⁸⁶Sr in a belemnite from this zone in Morgan County, Colorado, yields a value of 0.707790 ± 0.000008 (2-sigma SE), nearly identical to that of a bivalve from the same zone in Niobrara County, Wyoming (McArthur et al., 1994). The western shoreline of the seaway during the time of H. birkelundae extended as far west as northwestern Colorado and southwestern Wyoming. en_US
dc.format.extent 4121121 bytes
dc.format.mimetype application/pdf
dc.language eng en_US
dc.language.iso en_US
dc.publisher New York, NY : American Museum of Natural History en_US
dc.relation.ispartofseries American Museum novitates ; no. 3388 en_US
dc.subject.lcc QL1 .A436 no.3388 2003 en_US
dc.subject.lcsh Ammonoidea -- Colorado. en_US
dc.subject.lcsh Mollusks, Fossil -- Colorado. en_US
dc.subject.lcsh Paleontology -- Cretaceous -- Colorado. en_US
dc.subject.lcsh Paleontology -- Colorado. en_US
dc.title Ammonites from the upper part of the Pierre Shale and Fox Hills Formation of Colorado. American Museum novitates ; no. 3388 en_US
dc.title.alternative Colorado ammonites en_US
dc.type text en_US

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  • American Museum Novitates
    Novitates (Latin for "new acquaintances"), published continuously and numbered consecutively since 1921, are short papers that contain descriptions of new forms and reports in zoology, paleontology, and geology. New numbers are published at irregular intervals.

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