Paleocene Mammals Research Articles

Cretaceous-Tertiary boundary in the Denver Basin, Colorado

Research Article| January 01, 1943 Cretaceous-Tertiary boundary in the Denver Basin, Colorado ROLAND W. BROWN ROLAND W. BROWN Search for other works by this author on: GSW Google Scholar GSA Bulletin (1943) 54 (1): 65–86. https://doi.org/10.1130/GSAB-54-65 Article history received: 05 Jun 1942 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation ROLAND W. BROWN; Cretaceous-Tertiary boundary in the Denver Basin, Colorado. GSA Bulletin 1943;; 54 (1): 65–86. doi: https://doi.org/10.1130/GSAB-54-65 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Field work by the writer during 1939, 1940, and 1941 resulted in the discovery of Paleocene mammals only 50 feet above the highest remains of Triceratops in the Denver Basin, Colorado. This new evidence checks that of the floras, and thus indicates within relatively narrow limits the position of the Cretaceous-Tertiary boundary in that area. As this boundary definitely places the basal portion of the Denver formation and Dawson arkose in the Upper Cretaceous sequence, some changes in the nomenclature of these and other strata adjacent to the boundary become necessary. Stratigraphic and paleontologic evidence shows that the Laramie formation, Arapahoe formation, and the Cretaceous parts of the Denver formation and Dawson arkose comprise a unit correlative with the Lance formation and its equivalents. Therefore, the writer proposes that the Laramie be redefined to include all the Upper Cretaceous sequence between the top of the Fox Hills and the base of the Paleocene in the Denver Basin; that the term Arapahoe as Arapahoe conglomerate member be retained for the conglomerate immediately overlying the present Laramie formation; and that the terms Denver formation and Dawson arkose be restricted to the Tertiary strata. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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