COPROLITE

Map showing the geographic distribution of the Morrison Formation across the Western Interior of the conterminous United States based on subsurface data and outcrop exposures (base map from Peterson, 1972). Open circles-reconnaissance localities for carbonate deposits; dark circles-detailed carbonate wetland/lacustrine sections; dark triangles-detailed Brushy Basin section. 1 (Belt, MT), 2 (Big Horn National Recreation Area, WY), 3 (Thermopolis, WY), 4 (Arminto, WY), 5 (Como Bluff, WY), 6 (Park Creek Reservoir, CO), 7 (Highway 287 roadcut, north of Ft. Collins, CO), 8 (Horsetooth Reservoir, CO), 9 (I-70 roadcut, Denver, CO), 10 (West Alameda Parkway, Morrison, CO), 11 (Gunnison, CO), 12 (Cope's Nipple, Cañon City, CO), 13 (Skyline Drive, Cañon City, CO), 14 (Marsh-Felch Quarry, Cañon City, CO), 15 (Bravo Canyon, near Purgatoire River, CO), 16 (Dinosaur National Monument, Vernal, UT), 17 (Cleveland-Lloyd Quarry, near Price, UT), 18 (Moore Cutoff, near Moore, UT, in the San Raphael Swell), 19 (Colorado National Monument, CO), 20 (Fruita, CO), 21 (Dewey Bridge, UT), 22 (Escalante Canyon, CO), 23 (Blue Mesa, CO), 24 (Vancorum, CO), 25 (Lisbon Valley, CO), 26 (Norwood Hill, CO), 27 (Big Gypsum Valley, CO), 28 (Montezuma Creek, UT), 29 (McElmo Canyon, CO), 30 (Durango, CO), 31 (Piedra River, CO), 32 (Four Corners, CO), 33 (Beclabito, NM), 34 (Oak Springs, NM), 35 (Sanostee Wash, NM), 36 (Toadlena, NM), 37 (Goat Mountain, NM), 38 (Blue Peak, NM), 39 (Galisteo Dam, NM), 40 (Capulin Peak, NM), 41 (Deadmans Peak, NM). See Turner-Peterson (1987), Turner and Fishman (1991), and Dunagan (1998) for detailed locality information.

Fossil content
Main article: List of Paleobiota of the Morrison Formation
Main article: List of dinosaurs of the Morrison Formation

Though many of the Morrison Formation fossils are fragmentary, they are sufficient to provide a good picture of the flora and fauna in the Morrison Basin during the Kimmeridgian. Overall, the climate was dry, similar to a savanna but, since there were no angiosperms (grasses, flowers, and some trees), the flora was quite different. Conifers, the dominant plants of the time, were to be found with ginkgos, cycads, tree ferns, and horsetail rushes. Much of the fossilized vegetation was riparian, living along the river flood plains. Along the rivers, there were fish, frogs, salamanders, lizards, crocodiles, turtles, pterosaurs, crayfish, clams, and mammaliforms.

The dinosaurs were most likely riparian, as well.[6] Hundreds of dinosaur fossils have been discovered, such as Allosaurus, Ceratosaurus, Torvosaurus, Saurophaganax, Camptosaurus, Ornitholestes, several stegosaurs comprising at least two species of Stegosaurus and the slightly older Hesperosaurus, and the early ankylosaurs, Mymoorapelta and Gargoyleosaurus, most notably a very broad range of sauropods (the giants of the Mesozoic era). Since at least some of these species are known to have nested in the area (Camptosaurus embryoes have been discovered), there are indications that it was a good environment for dinosaurs and not just home to migratory, seasonal populations. However, the large body mass of the sauropods has been interpreted as an adaptation to migration in times of drought.[6]

Sauropods that have been discovered include Diplodocus (most famously, the first nearly complete specimen of D. carnegii, which is now exhibited at the Carnegie Museum of Natural History, in Pittsburgh, Pennsylvania), Camarasaurus (the most commonly found sauropod), Brachiosaurus, Apatosaurus, Brontosaurus, Barosaurus, the uncommon Haplocanthosaurus and Supersaurus. The very diversity of the sauropods has raised some questions about how they could all co-exist. While their body shapes are very similar (long neck, long tail, huge elephant-like body), they are assumed to have had very different feeding strategies, in order for all to have existed in the same time frame and similar environment.

The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.
Contents

1 Fauna comparisons
2 Ornithischians
2.1 Neornithischians
2.2 Thyreophorans
2.3 Misc
3 Sauropods
3.1 Haplocanthosaurids
3.2 Rebbachisaurids
3.3 Dicraeosaurids
3.4 Diplodocids
3.5 Macronarians
4 Theropods
4.1 Carnosaurs
4.2 Ceratosaurs
4.3 Coelurosaurs
4.4 Megalosauroids
5 Eggs
6 Tracks
6.1 Ornithopods
6.2 Stegosaurs
6.3 Theropods
7 Footnotes
8 References

Fauna comparisons

The fauna of Morrison Formation is similar to one in the coeval rocks of Tendaguru Beds (in Tanzania) and Lourinhã Formation in Portugal,[1] mostly with the second. Some genera are shared in Morrison and Lourinhã, such as Torvosaurus,[2] Ceratosaurus,[3] Stegosaurus, Dryosaurus,[4] and Allosaurus.[5] In sum, Morrison Fm has 37 valid genera of dinosaurs.
Ornithischians

The herbivorous ornithischian dinosaurs were diverse but not as common as sauropods in the Morrison. Fruitadens, previously known as the "Fruita Echinodon", was found to be a heterodontosaurid. Plate-backed stegosaurids included Hesperosaurus mjosi, Stegosaurus armatus, S. ungulatus, S. stenops, and Alcovasaurus longispinus. Armored dinosaurs that weren't stegosaurs were unknown in the formation until the 1990s. Two have been named: Gargoyleosaurus parkpinorum and Mymoorapelta maysi. Ornithopods, bipedal herbivores, came in several types. Small "hypsilophodonts" included Drinker nisti, Laosaurus celer, "L." gracilis, Nanosaurus agilis, Othnielia rex, and Othnielosaurus consors. Larger but similar-looking dryosaurids were represented by Dryosaurus altus and the camptosaurid Uteodon aphanoecetes, which is currently known only from Dinosaur National Monument. Still larger was the more common Camptosaurus dispar. Dryosaurids and camptosaurids were early iguanodonts, a group that would later spawn the duck-billed dinosaurs.
Neornithischians

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.