Pabian, R. K., Diffendal, R. F., Jr., 1981. Geology of Lake McConaughy Area, Keith County, Nebraska (FG-10) 21 pp., size 8.5" x 11". Description: Rocks cropping out along the North Platte River valley at Lake McConaughy provide excellent exposures of the Ogallala Group, deposited during the Miocene epoch of the Tertiary period. Easily accessible, the Ogallala outcrops contain locally abundant fossils of seeds, casts of pedotubles, and occasional fossils of vertebrate animals such as rhinoceroses, horses, elephants, and camels. The Lake McConaughy area is significant to the state both geologically and economically because it is underlain by water-saturated gravel and sandstone deposits that yield water for irrigation, livestock use, and human consumption.