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Mineral Resources > Online Spatial Data > Geology > by state > Colorado Geology

Geologic units in Crowley county, Colorado

Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.9 % of this area

Includes Broadway and Louviers Alluviums

Lithology: gravel; alluvium

Pierre Shale--Middle unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 20 % of this area

In Boulder-Fort Collins area, contains Richard, Larimer, Rocky Ridge, Terry, and Hygiene Sandstone Members; elsewhere shale between zones of Baculites reesidei and B. scotti

Lithology: shale; sandstone

Pierre Shale--Upper unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 0.6 % of this area

Lithology: shale

Older gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 16 % of this area

Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest

Lithology: gravel; alluvium

Eolian deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 33 % of this area

Includes dune sand and silt and Peoria Loess

Lithology: dune sand; silt; loess

Modern alluvium (Phanerozoic | Cenozoic | Quaternary) at surface, covers 3 % of this area

Includes Piney Creek Alluvium and younger deposits

Lithology: alluvium

Pierre Shale--Lower unit (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 21 % of this area

Sharon Springs Member (organic-rich shale and numerous bentonite beds) in lower part

Lithology: shale; bentonite

Niobrara Fm (Phanerozoic | Mesozoic | Cretaceous) at surface, covers 4 % of this area

Calcareous shale and limestone

Lithology: shale; limestone