Dinosaurs

The board's count of tyrannosaurs has a complication from this county. In the summer of 2006 Clayton Phipps and his crew, prospecting a Garfield County ranch owned by Lige and Mary Ann Murray, dug out a Triceratops tangled with a small tyrannosaur. The pair went to the North Carolina Museum of Natural Sciences, bought for it in 2020, and in Nature on October 30, 2025, Lindsay Zanno and James Napoli concluded that the small one was no young T. rex but a grown Nanotyrannus lancensis, a second tyrannosaur of the same time.

What the plaque says

Dinosaurs Its difficult to believe now, but 65 million years ago the middle of this continent was a shallow sea. The area, when not underwater, was part of a hot, humid subtropical coastline of marshes, rivers and river deltas bearing dense vegetation near the water courses and grassy plains farther to the west. Fossils tell us that turtles, crocodiles, lizards, toads, fishes, small primitive mammals and dinosaurs lived on this coastal plain. The dinosaurs included species like Tyrannosaurus, Triceratops, Edmontosaurus, Ankylosaurus and Pachycephalosaurus. Many of the most complete specimens of these species on display worldwide were gathered here in Garfield and McCone Counties. The first Tyrannosaurus rex skeleton came out of these hills in 1902. In fact, half of the 30 some tyrannosaurs found in the world are from this area. The rock unit that these fossils come from is called the Hell Creek Formation and extends over much of eastern Montana and the Dakotas. Displays of the dinosaurs found in this area can be seen in the Garfield County Museum, the Fort Peck Interpretive Center at Fort Peck Dam and the Museum of the Rockies in Bozeman.

Where it stands

More markers nearby

• Fort Peck Dam and Lake — steps away
• Join the Voyage of Discovery — steps away
• Brockway, Montana — 19 mi