It dates to the Late Cretaceous, between 79 and 75.3 million years ago,[4] corresponding to the "Judithian" land vertebrate age.

[6] It is an historically important formation, explored by early American paleontologists such as Edward Drinker Cope, who named several dinosaurs from scrappy remains found here on his 1876 expedition (such as Monoclonius).

[7] The McClelland Ferry Member (78.7-76.3 Ma) is believed to be equivalent to the Oldman Formation, with the Coal Ridge Member (76.3-75.3 Ma) equivalent to the Dinosaur Park Formation.

Hip bones, possibly representing a North American member of the European spadefoot toad family are also known from the formation.

Brachychampsa B. montana Leidyosuchus L. canadensis Chamops C. segnis Exostinus E. lancensis A knob-scaled lizard.

[21] Paleoscincus P. costatus "Tooth,"[10] type specimen A dubious ankylosaur Probrachylophosaurus P. bergei A brachylophosaurin hadrosaur Pteropelyx P. grallipes "Skeleton lacking skull.

"[22] A dubious hadrosaurid Trachodon T. mirabilis Isolated teeth, type specimen[10] A dubious hadrosaurid Albertaceratops A. nesmoi[23] Reclassified as Medusaceratops lokii Avaceratops A. lammersi[23] "[Two] partial skulls, skeleton, juvenile,"[24] type specimen A ceratopsid Ceratops C. montanus "occipital condyle, paired horn cores,"[25] type specimen A dubious ceratopsid Dysganus D. bicarinatus "Isolated teeth.

"[24] Type specimen A dubious ceratopsid Dromaeosaurus D. albertensis Teeth[33] A dromaeosaurid, also found in the Dinosaur Park Formation D. explanatus "Tooth.

"[34] Possible relative of Saurornitholestes Zapsalis[35] Z. abradens "Teeth,"[34] type specimen A dromaeosaurid Troodon T. formosus Teeth (type specimen),[10][33] egg A troodontid, possibly dubious.

"[46] A possible troodontid or juvenile tyrannosaurid Paronychodon P. lacustris Teeth, type specimen An indeterminate maniraptoran, also found in the Dinosaur Park, Milk River, and Kirtland Formations Basilemys B. sp.