Question: Which of the three geological formations exposed in the Como Bluff was named for a post office on the eastern side of the Bighorn Basin in Wyoming?  
Context: The Bighorn Basin Dinosaur Project (BBDP) is a paleontological research and education group focusing on the Mesozoic ecosystems of the Bighorn Basin in northern Wyoming and southern Montana, U.S.A. Anolbanolis is an extinct genus of iguanian lizards that lived in the Bighorn Basin of what is now Wyoming during the earliest Eocene.  The type species "A. banalis" was named by paleontologist Krister Smith in 2009 from a collection of isolated skull fragments found in a layer of the Willwood Formation that dates to a brief period of global warming called the Paleocene-Eocene thermal maximum (PETM) about 56 million years ago.  The genus name "Anolbanolis" means "poor anole" from the Greek "anolbos" ("poor, wretched") and the name "Anolis", in reference to the scrappy nature of known fossil material and its close resemblance to lizards in the genus "Anolis".  Smith suggested that "Anolbanolis" may be a close relative of "Anolis" or "Polychrus", which are common today in Central and South America but not found as far north as Wyoming, fitting with the idea that the Bighorn Basin was warmer and wetter in the Eocene than it is currently.  According to Smith, the species name "banalis" is a reference to it being a "banal" lizard in the Willwood, being "quite abundant in the type locality," and not unusual because "the discovery of Eocene boreal fossil members of living subtropical and tropical clades is becoming commonplace."  In 2011 Smith named a second species of "Anolbanolis", "A. geminus", which lived in the Bighorn Basin shortly after the PETM and was about 50 percent larger than "A. banalis".  Smith concluded on the basis of features in "A. geminus" that "Anolbanolis" is more closely related to "Anolis" than it is to "Polychrus". The Cloverly Formation is a geological formation of Early Cretaceous age (Aptian to Albian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States.  It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904.  The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. The Bad Pass Trail, also known as the Sioux Trail, was established by Native Americans on the border of present-day Montana and Wyoming as a means of access from the Bighorn Basin in Wyoming to Bison-hunting grounds in the Grapevine Creek area of Montana.  Marked by stone cairns, the trail led across Bad Pass and was established in pre-Columbian times.  After Europeans arrived in the area it was frequented by fur trappers and mountain men, beginning in 1824.  Trappers assembled pack trains at the junction of the Shoshone River and the Bighorn River, using the Bad Pass Trail to avoid Bighorn Canyon.  The trail ended at the mouth of Grapevine Creek on the Bighorn, from which the pack train could float down the Bighorn on rafts to the Yellowstone River and then to the Missouri and on to St. Louis. Suzanniwana is an extinct genus of iguanian lizards that lived in western North America during the earliest Eocene, approximately 56 million years ago.  Two species are known from the Bighorn Basin of Wyoming: the type species "S. patriciana" named in 2009, and the species "S. revenanta" named in 2013.  "Suzanniwana" lived during the Paleocene–Eocene Thermal Maximum, a brief period of global warming that resulted in warmer and drier conditions in the Bighorn Basin.  It likely stemmed from a lineage that had migrated into the basin from regions farther to the south, following a latitudinal band of constant climatic conditions that moved northward as the planet warmed (a phenomenon known as habitat tracking).  "Suzanniwana" shares many skeletal features with modern casquehead lizards of the family Corytophanidae and may be a stem-corytophanid.  It also closely resembles "Geiseltaliellus", an iguanian from the middle Eocene Messel pit in Germany. Enneabatrachus hechti is an extinct species of an extinct genus of prehistoric frog known from the late Jurassic Morrison Formation.  Its remains have been recovered from stratigraphic zone 5.  One specimen has been recovered from Quarry 9 of Como Bluff in Wyoming and another specimen was later reported from Dinosaur National Monument.  A small discoglossid frog whose name means "nine frog" after the quarry in which it was discovered.  The Como Bluff specimen was an illium only a few millimeters long.  "E. hechti"<nowiki>'s</nowiki> live weight would have only been a few grams. Como Bluff is a long ridge extending east-west, located between the towns of Rock River and Medicine Bow, Wyoming.  The ridge is an anticline, formed as a result of compressional geological folding.  Three geological formations, the Sundance, the Morrison, and the Cloverly Formations, containing fossil remains from the Late Jurassic of the Mesozoic Era are exposed.  Nineteenth century paleontologists discovered many well-preserved specimens of dinosaurs, as well as mammals, turtles, crocodilians, and fish from the Morrison Formation.  Because of this, Como Bluff is considered to be one of the major sites for the early discovery of dinosaur remains.  Among the species discovered is the only known specimen of "Coelurus".  Significant discoveries were made in 22 different areas scattered along the entire length of the ridge.  It is included on the National Register of Historic Places as well as the National Natural Landmark list. Basin is a town in, and the county seat of, Big Horn County, Wyoming, United States.  The population was 1,285 at the 2010 census.  The community is located near the center of the Bighorn Basin with the Big Horn River east of the town.  Basin's post office, built in 1919, is listed on the National Register of Historic Places. The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming in the United States.  It is bounded by the Absaroka Range on the west, the Bighorn Mountains on the east, and the Owl Creek Mountains and Bridger Mountains on the south.  It is drained to the north by tributaries of the Bighorn River, which enters the basin from the south, through a gap between the Owl Creek and Bridger Mountains, as the Wind River, and becomes the Bighorn as it enters the basin.  The region is semi-arid, receiving only 6–10 in (15–25 cm) of rain annually. The Farm Creek Section, also known as the Farmdale Geologic Exposure, is a hillside near East Peoria, Illinois that clearly showed geological strata.  It is nationally significant as one of the first exposed glacial stratifications in the United States to be scientifically documented.  These Ice Age geological formations, with rock layers representing different periods of glaciation, had long been known and published in England, France, and Germany, but were not yet well known in North America.  Geologist Frank Leverett discovered this exposed face of a hill with its clearly defined stratifications in 1879 and described and pictured it in his monograph, "The Illinois Glacial Lobe", in 1899.
Answer: The Cloverly Formation