Formation
body of rock identified by lithic characteristics and stratigraphic position; it is usually but not necessarily tabular and is mappable at the Earth's surface or traceable in the subsurface. Smaller than a subgroup
Giessen nappe
Temple Butte Limestone
Cherry Canyon Formation
Margaret Formation
Bell Canyon Formation
Doughnut Formation
Horseshoe Canyon Formation
Santa Maria Formation
Marcellus Formation
Lower Keuper
Punta Judas Formation
Los Molles Formation
Merlis Serpentinites
Lunz Formation
Bissett Formation
Boone Formation
Ingersoll Shale
Bull Run Formation
New Egypt Formation
Cliff House Sandstone
Fernando Formation
Pico Formation
Hidden Valley Dolomite
Lost Burro Formation
Borden Formation
Brule Formation
Lake Waco Formation
Hensel Formation
Great Valley Sequence
Hermit Formation
Rove Formation
Snow Hill Island Formation
Thames Group
Bell Ranch Formation
Bet-Meir Formation
La Boca Formation
Gypsum Spring Formation
Sonoma Volcanics
Jordan Formation
Vishnu Basement Rocks
Santana Formation
Rockwell Formation
Portland Formation
Heiberg Formation
Jing Chuan Formation
Alamosa Formation
Sheep Pen Sandstone
Maroon Formation
Animas Formation
Poison Canyon Formation