Aladdin, Crook Co., Wyoming, USA

Age: Late Cretaceous (66 - 100.5 Ma)

Lithology: Siltstone,shale,sandstone

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Age: Mesozoic (100.5 - 163.5 Ma)

Stratigraphic Name: Cloverly Formation; Morrison Formation

Description: Cloverly Formation (North and South Wyoming) - Rusty sandstone at top, underlain by brightly variegated bentonitic claystone; chert-pebble conglomerate locally at base. Cloverly Formation (Northeast Wyoming - Hartville Uplift) - Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. Morrison Formation (North and South Wyoming) - Dully variegated claystone, nodular limestone, and gray silty sandstone. In southern Yellowstone and Jackson Hole areas the presence of Morrison is questionable. Morrison Formation (Northeast Wyoming) - dully variegated siliceous claystone, nodular white limestone, and gray silty sandstone. Inyan Kara Group (Northeast - Black Hills) - Rusty to light-gray sandstone containing lenticular chert-pebble conglomerate interbedded with variegated bentonitic claystone. Includes Fall River and Lakota Formations.

Lithology: Major:{sandstone,claystone}, Minor:{conglomerate,limestone}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Age: Jurassic (145 - 163.5 Ma)

Stratigraphic Name: Morrison Formation

Description: Light greenish-gray to green, pink and grayish-red siltstone and claystone accompanied by thin, lenticular light-gray sandstones and shaly limestones; formation may be totally absent in some areas to as much as 145 feet (44 m) thick, but generally ranges from 80 to 100 feet (24 to 30 m) thick across the map area (Robinson and others, 1964). The upper part of the formation is darker colored and noncalcareous, whereas the lower part is lighter and calcareous. Locally, the upper part may contain barite nodules up to 2 inches in diameter (Bergendahl, Davis, and Izett, 1961). The lenticular sandstones, which are well-sorted, very fine-grained, and weakly cemented are typically less than 6 feet thick, occasionally crossbedded and ripple-marked, and are concentrated in the lower part of the formation. The limestone lenses similarly concentrate in the lower part of the formation. Contact with the underlying Sundance Formation is gradational over a very short distance, and is picked at the top of a persistent bed of yellow-weathering sandstone. This contact represents a transition from the underlying marine rocks of the Sundance Formation to the nonmarine strata of the Morrison (Robinson, Mapel, and Bergendahl, 1964).

Reference: Sutherland, W.M. Preliminary Geologic Map of the Devils Tower 30'x60' Quadrangle. Wyoming State Geological Survey Open File Report 2007-06. [109]