Digging into the Past: The Judith River Formation

Did you know?

Two ankylosaurid species from the Judith River Formation are known: the nodosaurid Edmontonia longiceps and the ankylosaurid Zuul crurivastator. These quadrupedal herbivorous dinosaurs were heavily armoured, with osteoderms covering their bodies.

Step into the world of fossil excavation where every discovery uncovers Earth’s palaeontological secrets!

Beneath Montana’s rugged landscapes hides a prehistoric world waiting to be uncovered. From towering dinosaurs to prehistoric reptiles, every fossil discovery brings us closer to understanding life millions of years ago.

One of Montana’s most significant fossil sites, the Judith River Formation, has been a hotspot for palaeontologists for over a century revealing incredible palaeontological information. This ancient palaeoenvironment once teeming with dinosaurs, crocodiles, turtles, fish, and amphibians, offers a glimpse into a vanished world.

Exploring the Judith River Formation

The Judith River Formation in Montana, USA.
  • Age: 79–75.3 million years old.
  • Formation: Underlies the Bearpaw Formation.
  • Geology: Mudstone, siltstone, and sandstone layers preserving biodiverse palaeoenvironment.
  • Fossils Found: Dinosaurs, crocodiles, turtles, fish, & amphibians.

The Judith River Formation has been a hotspot for palaeontologists since Edward Drinker Cope’s legendary 1876 expedition, during the fierce Bone Wars a time when fossil hunters raced to uncover the most spectacular dinosaur finds.

Fossil Highlights from My Excavation

In June 2024, I had the incredible opportunity to join the Badlands Dinosaur Museum for hands-on fieldwork in Montana. Every fossil uncovered adds a crucial piece to the puzzle of Montana’s Late Cretaceous history, bringing dinosaurs and more into the spotlight.

Here are some of the most exciting finds from my excavation:

  • Tyrannosaurid Teeth – Razor-sharp, serrated, & built for crushing bone. These fearsome predators ruled the Late Cretaceous landscape.
  • Hadrosaurid Tendon – Ossified tendon from duck-billed dinosaurs who grazed within the swamp lands near the Western Interior Seaway.
  • Ceratopsian Teeth – A glimpse into the world of horned dinosaurs like Avaceratops which once grazed across ancient floodplains.
  • Ankylosaurid Scute – The bony rugged armour of a tank-like dinosaur, built for defence against predators.
  • Banded Crocodile Tooth – Evidence of prehistoric crocodilians lurking in long gone rivers.
  • Turtle Shell Pieces – Remnants of ancient turtles that once swam in the Western Interior Seaway.

Excavating the Late Cretaceous Bonebed

Fieldwork in Montana is an adventure in itself. The Judith River Formation offers a rare opportunity to unearth fossils embedded in layers of geological strata. Here are some highlights from my excavation:

  • Judith River Formation Fossils – A collection of fossilised remains, including turtle, crocodile, & dinosaur specimens.
  • Excavation Process – Carefully uncovering fossil material, preparing specimens for study, & documenting each find.
  • Field Discoveries – From tyrannosaurid teeth to ceratopsian fossils, each discovery adds to our understanding of Montana’s geological history.

  • Excavating the Late Cretaceous bonebed layer.
  • Turtle shell piece.
  • Banded crocodile tooth.
  • Ankylosaurid scute.
  • Ceratopsian tooth.
  • Tyrannosaurid tooth.
  • Second tyrannosaurid tooth.
  • Another angle of the second tyrannosaurid tooth I discovered.
  • Third and final tyrannosaurid tooth.
  • Photo with the final tyrannosaurid tooth I found on my last field day.
  • Dinosaur caudal vertebrae (tail vertebrae) .
  • Big turtle shell piece I found and excavated.
  • Big turtle shell piece excavated ready for plastering.
  • Excavating the Late Cretaceous bonebed.

You can learn more about the palaeoenvironment of the Judith River Formation in this ambassador blog article below.

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