Niobrara Formation

[Meek, F.B., and Hayden, F.V., 1862, Descriptions of new Lower Silurian, (Primordial), Jurassic, Cretaceous, and Tertiary fossils, collected in Nebraska, by the exploring expedition under the command of Capt. Wm. F. Raynolds, U.S. Topographical Engineer; with some remarks on the rocks from which they were obtained: Academy of Natural Sciences of Philadelphia Proceedings, December 31, 1861, v. 13, p. 415-447., [This paper by Meek and Hayden described the rocks of Nebraska, which at that time included Wyoming, Montana, and the Dakotas]]( Named as top formation of Lower Cretaceous series, top of Lower Cretaceous. Formerly called "formation No. 3" (Meek and Hayden, 1857). Type not designated. Named for Niobrara River, Knox Co, NE in Salina basin, where formation forms 90-100 ft cliffs near mouth along Missouri River. Consists of lead-gray, calcareous marl that weathers to light buff or whitish color resembling true chalk; lower part grades into more compact beds of soft, bluish-gray limestone; locally weathers to hard, whitish limestone. Traced in outcrop from northeastern KS through AR into TX and NM. Occurs in Black Hills and along Rocky Mountains. Invertebrate fossils listed. Dakota Group (new), Fort Benton Group (new), and Niobrara Division together represent the Lower, or Gray Chalk, and probably the Upper Green Sand of British geologists (=Turonien and Cenomanien of D'Orbigny). Newton, Henry, and Jenney, C.P., 1880, Report on the geology and resources of the Black Hills of Dakota: U.S. Geological and Geographical Survey, Rocky Mountain region Atlas (Powell), 555 p. Recognized for first time on west side of Beaver Creek, on the Belle Fourche near the Great Bend, and near Bear Butte in the Black Hills area, Pennington Co, SD in the Williston basin. Estimated at 100 to 200 ft thick. Divided into the newly named Timpas formation (base) and Apishapa formation (top) in Otero Co, CO on the Las Animas arch. Composed of about 700 ft of shale and some limestone. Overlies Dakota sandstone; underlies Pierre group. Is of Cretaceous age. Shows outcrop and describes formation in southern part of Black Hills, WY and SD and areas to the south including Old Woman anticline, eastern Converse Co [now Niobrara Co] WY in Powder River and Williston basins and on Chadron arch. Consists of chalk and calcareous shale. Average thickness 225 ft. Underlain by Carlile formation; overlain by Pierre shale. Late Cretaceous in age. Thom, W.T., Jr., 1923, Oil and gas prospects in and near the Crow Indian Reservation, Montana, IN Contributions to economic geology (short papers and preliminary reports), 1922; Part 2, Mineral fuels: U.S. Geological Survey Bulletin, 736-B, p. B35-B53. Revised in that Niobrara shale of the Colorado group underlies the newly named Telegraph Creek formation. Telegraph Creek occurs at the head of Telegraph Creek, T2S, Rs28 and 29E, Yellowstone Co, MT on the Central Montana uplift. Is of Late Cretaceous age. Rubey, W.W., 1931, Lithologic studies of fine-grained Upper Cretaceous sedimentary rocks of the Black Hills region, IN Shorter contributions to general geology, 1930: U.S. Geological Survey Professional Paper, 165-A, p. A1-A54. Lower contact revised and formation subdivided into Sage Breaks shale member (new), 250-325 ft thick, and overlying Beaver Creek chalky member (new), 125-200 ft thick on west side of the Black Hills, northeastern WY and southeastern MT in the Williston and Powder River basins. Overlies Turner sandy member (new) of the Carlile shale, underlies Gammon ferruginous member (new) of the Pierre shale. Rocks of Sage Breaks shale member were included in Carlile shale of previous reports. Samples of Upper Cretaceous claystone, shale, and marl, including a sample from Beaver Creek chalky member, compared for their mineralogy, chemical composition, grain size, density, porosity, fissility, and bedding laminations. A formation in the Colorado group. Late Cretaceous in age. Reeside, J.B., Jr., 1944, Maps showin