ammonites
Egg Island, MOR TM-024 (Cretaceous of the United States)

Where: Teton County, Montana (47.8° N, 112.2° W: paleocoordinates 55.5° N, 78.6° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Two Medicine Formation, Campanian (83.5 - 70.6 Ma)

• unlabeled section shows that fossils are distributed in several horizons, but no details given

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; lithified, brown, argillaceous carbonate and mudstone

• interpreted as the products of soil formation where partially dried sediments were repeatedly disrupted and mixed in the process of nest construction and daily traffic; "carbonate-rich paleosols and overbank deposition"
• brown, organic-rich, siliceous carbonates with mudstone inclusions; "interbedded calcretes and mudstones"

Size class: macrofossils

Collected by J. Horner, D. Varricchio in 1983-

Collection methods: quarrying, mechanical, hydrochloric,

Primary reference: J. R. Horner. 1982. Evidence of colonial nesting and "site fidelity" among ornithischian dinosaurs . Nature 297(5868):675-676 [M. Carrano/M. Carrano/M. Carrano] more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 13281: authorized by Matt Carrano, entered by Matt Carrano on 13.02.2002

Creative Commons license: CC BY-NC-ND (attribution-noncommercial-no derivatives)