Abstract Stratification and estimated paleoflow conditions for valley-fill deposits suggest that Ogallala Group streams in western Nebraska were similar to modern streams of south-central Alberta. Ogallala stratification includes medium-scale (0.5 to 2.0 m thick) trough crossbedded sand and gravel, tabular indistinctly horizontally bedded and imbricated gravel, and horizontally bedded sand and pebbly sand. Valley fills are 15 to 55 m thick and 800 to 1800 m wide at the top. Some are in bedrock-floored channels resembling the “inner channels “ of Shepherd and Schumm (1974). Gradients for three well exposed paleovalley floors range from 0.0014 to 0.0020 (m/m) after tectonic correction. This compares with 0.00135 for the modern North Platte River Valley in Nebraska. The average intermediate diameters of the 10 largest clasts from tabular gravel beds found at 17 sites varied between 0.077 and 0.15 m. The average median intermediate diameter for gravel from four well exposed tabular gravel beds is 0.024 m. Consistent paleodepth estimates of about 2 m correlate well with the scale of cross-stratification observed in the valley fills. Paleo-velocities are estimated at about 2 m/sec, and Froude numbers of about 0.4 are consistent with a lower flow regime in the stability field of dunes. Two-dimensional specific in-channel paleodischarges were 3 to 4 m 2 /sec. Total paleodischarge estimates based on slope-discharge relationships for gravel-bed rivers range from 340 to 1240 m 3 /sec and are comparable to average annual peak discharges on the North Platte River reported 80 to 90 years ago. Ogallala streams were probably dominated by macroforms similar to the “crescent-shaped bars” of the North Saskatchewan River. Deposition also took place on longitudinal bars in deeper channels. Shallow upper-flow regime transport and deposition is recorded by horizontally bedded sand and pebbly sand.

Abstract The Duer Ranch locality is situated on either side of U.S. 26 in southeastern Merrill County, Nebraska, halfway between the villages of Lisco and Broadwater and about 54 mi (90 km)southeast of Scottsbluff, Nebraska. The Rush Creek Land and Livestock Company currentlyowns all of sections 28, 29, 33, 34, and 35 of T. 19 N., R.47 W., as well as parts of sections 2, 3, 4, 10, and 11 of T. 18N., R.47W. (Broadwater and Tar Valley SW, 7½-minute Quadrangles; Fig. 1). The owners have allowed geologists to study the exposures on ranch property providedthat visitors stop at the ranch headquarters (Fig. 1) and obtain permission from the ranch foreman. Vehicles shouldbe parked inside the gate on thenorth side of U.S. 26 in the SW¼ Sec. 3, T.18N., R47.W. (Fig. 1), and all study ofthe site should be done on foot.Be certain to closeany gates that you open, anddo not smoke on the property. Rattlesnakes are found on the ranch. If you have asmall group and wish to examine the exposures in the southeast corner of the locality, two vehicles can park safely along the north side of the road cut on U.S. 26 in the NE¼ NW¼ sec. 10, T.18N., R.47W.

Abstract Ash Hollow State Historical Park, administered by the Nebraska Game and Parks Commission, is located primarily in Sec. 3, N½, Sec. 10, and the E½NE¼Sec.22, T.15N., R.42W. (Fig. 1), Garden County, Nebraska. The park and adjacent lands are shown on the Lewellen and Ruthton 7½ -minute Quadrangles; scale 1:24,000. U.S. 26 passes through the park. This highway and other paved roads provide access from 1-80. A camping area and a museum with excellent interpretive displays are located in the park. Rock exposures are easily accessible by foot in the park and at road cuts along U.S. 26 and nearby county roads. No collecting of specimens is permitted in the park, but samples may be collected from road cuts. Fossils found by people in and near the park have been added to the museum collections. Poison ivy can be found in abundance in some parts of the area. Rattlesnakes may live anywhere in this part of Nebraska.