2022-05-10_GENERAL DOCUMENTS - M1993041

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i 27 mapped in the Dowe Flats area (Masters 1957) . An 11-foot thick limestone unit 100 feet above the base of the Smoky Hill Member was mapped by Mailed in Dowe Flats, but was not described by Quam in the Little Thompson River outcrop. All the other materials in the bottom 200 feet of the Smoky Hill Member are dark gray to black, pyritiferous, cancerous, marine shales. A second 20-foot thick limestone bed was mapped at Dowe Flats and measured in the Little Thompson outcrop at the interval from 200 to approximately 220 feet above the bottom of Smoky Hill. A final limestone bed, with a base about 256 feet above the Smoky Hill Member, was also located in both field efforts: however, its thickness was measured as 12 feet by Mailed (1962) and 43 feet by Quam (1932) . Based upon interpretation of geophysical logs form oil exploration wells drilled 10 to 15 miles south and east of the site (Lowman 1977) , the 43 foot value appears to be more realistic. The Niobrara Formation is the only formation mined at Dowe Flats, with the Fort Hays member being the source of limestone. The lower Pierre Shale is the uppermost unit considered in this report. Only the lower 500 feet of the Pierre Shale are found in Dowe Flats; the remainder has been eroded away. The lower portions of Pierre Shale are homogeneous dark brown to gray-black marine shale that weathers to a buff color. The basal portion of the Pierre Shale, immediately above the Niobrara Formation, is sandy, but the sand content decreases in the main portion of the shale. 2. 3 Prehistoric Context The Colorado Historical Society (CHS) through the Office of Archaeology and Historic Preservation published several prehistoric and historic contexts for the northeastern Colorado region that includes Dowe Flats. The documents are part of the Resource Protection Planning Process (AM: RP3) . Jeffrey Eighmy authored the prehistoric context (1984) . The historic Euro- American context was written by Steven Mehls (1984) . The