Triceratops Frill Fossil | Cretaceous | Hell Creek Formation, Montana
Cretaceous (68 - 66 million years ago)
Private Ranch, Hell Creek Formation, Montana
Specimen size: approximately 14.75" long, 12" across, 0.5" thick
Triceratops is an extinct genus of herbivorous ceratopsid dinosaur, bearing a large bony frill and three horns on its large four-legged body. Triceratops lived during the Late Cretaceous Period, around 68 to 66.038 million years ago (mya) in what is now North America. Triceratops was one of the last dinosaur genera to appear before the great Cretaceous and Tertiary extinction event.
Individual Triceratops are estimated to have reached about 25.9–29.5 feet in length, 9.5–9.8 feet in height, 13,000-26,000 in weight. The most distinctive feature is their large skull, among the largest of all land animals. It could grow to be over 7 feet in length, and could reach almost a third of the length of the entire animal. It bore a single horn on the snout, above the nostrils, and a pair of horns approximately 3 feet long, with one above each eye.
The Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana.
The Hell Creek Formation occurs in Montana and portions of North Dakota, South Dakota, and Wyoming.
Strata in Hell Creek a series of fresh and brackish-water clays, mudstones, and sandstones deposited during the Maastrichtian, the last part of the Cretaceous period, by fluvial activity in fluctuating river channels and deltas and very occasional peaty swamp deposits along the low-lying eastern continental margin fronting the late Cretaceous Western Interior Seaway. The climate was mild, and the presence of crocodilians suggests a sub-tropical climate, with no prolonged annual cold. The famous iridium-enriched K–T boundary, which separates the Cretaceous from the Cenozoic, occurs as a discontinuous but distinct thin marker bedding within the Formation, near its uppermost strata.