Formation · Jurassic
Morrison Formation
Late Jurassic unit, Colorado · Utah · Wyoming · Montana
The Morrison Formation is the Late Jurassic sauropod bed of the American West, the source of Diplodocus, Camarasaurus, Apatosaurus, Stegosaurus and Allosaurus since the Bone Wars of the 1870s. Trade material is dominated by shed Allosaurus and Camarasaurus teeth, agatised bone slices, vertebra centra and isolated limb bones; articulated specimens command museum prices. Bone from the Brushy Basin Member is often heavily mineralised and red-brown; expect consolidant and crack fill on most pieces.
| Country | United States |
|---|---|
| Region | Colorado, Utah, Wyoming, Montana, New Mexico, Oklahoma |
| Age | Kimmeridgian, Late Jurassic |
| Age range | ~157–148 Ma |
| Member | Brushy Basin Member |
| Macrostrat rank | Fm· Macrostrat |
| Macrostrat age | 175–143 Ma· Macrostrat |
| Lithology | shale, mudstone, sandstone, siltstone, claystone, conglomerate· Macrostrat |
| Environment | fluvial indet., lacustrine indet., floodplain, fluvial-lacustrine indet., mire/swamp· Macrostrat |
| Macrostrat columns | 8 column(s) sampled from 8 unit(s)· Macrostrat |
| PBDB collections | 467 collections, 2016 occurrences· Paleobiology Database |
Collecting and legality
Commercial Morrison bone and teeth come from private quarries in Wyoming (Como Bluff area, Bone Cabin, Dana Quarry) and Colorado; Dinosaur National Monument and BLM land are off limits for sale material. Agatised Morrison bone sold as lapidary rough still needs a private-land source.
Lithology and setting
Variegated mudstones, channel sandstones and limestones of a vast semi-arid floodplain, with volcanic ash altered to bentonite in the Brushy Basin Member.
Commonly recorded taxa (PBDB)
Genera most often recorded from this unit in the Paleobiology Database (first 200 occurrences): Allosaurus (18), Camarasaurus (18), Stegosaurus (16), Diplodocus (12), Camptosaurus (10), Apatosaurus (6), Czekanowskia (6), Cladophlebis (5), Dryosaurus (4), Goniopholis (4), Brachyphyllum (3), Brontosaurus (3), Coelurus (3), Coniopteris (3), Equisetum (3).
Source: Paleobiology Database
Elsewhere
- Macrostrat: 1351
- macrostratConcept: 9394
- PBDB: strata:Morrison
- Wikidata: Q1195552
- Macrostrat stratigraphic name
- PBDB occurrences for this unit
- Wikipedia: Morrison Formation
- Mindat: Morrison Formation
Cite this article
Stratum Study. "Morrison Formation" (Formation). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/formations/morrison-formation. Accessed 2026-09-20.
@misc{stratum-morrison-formation,
title = {Morrison Formation},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/formations/morrison-formation}},
year = {2026},
note = {Formation article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, macrostrat, pbdb, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.