Pg. 409. Cap Rock Member of Ash Hollow Formation. Has been referred to as descriptive field term "Cap Rock Bed" by Frick Observatory field parties since 1927. Recognized in northern Nebraska and adjacent South Dakota. Consists mostly of gravel, sand, clay, ash indurated into caliche beds. Thickness 28 feet at type, varies from 25 to 50 feet. Overlies Burge Member of Valentine Formation of Ogallala Group; underlies unnamed deposits of the Ash Hollow. Age is Miocene.
Type locality (=Burge type): Burge quarry, on east side of Snake River, in N/2 NW/4 SE/4 sec. 15, T. 32 N., R. 30 W., Cherry Co., central northern NE.

Source: Publication; US geologic names lexicon (USGS Bull. 1520, p. 51).

Pg. 230 (fig. 3), 246 (fig. 4), 294 (fig. 13), 298-303, 304 (fig. 15), 338-345 (figs. 32-38). Cap Rock Member of Ash Hollow Formation of Ogallala Group. Calcareous sandstone that forms the rims of most canyons along the Niobrara River and its tributaries, central northern Nebraska. Includes Swallow ash (10.6 +/-0.2 Ma, Boellstorff and Skinner, 1977, p. 40) at its base. Is the lowest member of Ash Hollow; underlies Merritt Dam Member. Unconformably overlies Burge Member of Valentine Formation of Ogallala Group or, where absent, Devil's Gulch Member of Valentine; contact commonly placed at base of "fragmental layer" [approx. =†Minnechaduza Beds of Elias, 1942]. Fossils. Includes vertebrate Minnechaduza Fauna (=Valentine fauna of some 1930s paleontologists). Age is late Miocene (Clarendonian NALMA).

Source: Publication.