A New World: Tertiary Mammals

The panel's brontotheres have a local address. In 1903 W. D. Matthew and Earl Douglass described the fauna of what they called the Titanotherium beds at Pipestone Springs, west of Whitehall, naming the beds for the big horned brontotheres. The date has moved since: the Pipestone Springs Main Pocket is now placed in the Chadronian, the late Eocene, roughly 38 to 34 million years ago, rather than the Oligocene. Its richness is in small mammals, rabbit relatives and rodents above all, and its abundant coprolites have been studied to show which carnivores ate what.

What the plaque says

A New World: Tertiary Mammals Between the time dinosaurs went extinct 65 million years ago, and the beginning of the Ice Age, some 2 million years ago, is a time called the Age of Mammals. During this period of time the western third of Montana experienced a variety of geological activities, some of which raised mountains and lowered valleys. The valleys became the homes of a wide variety of interesting and bizarre animals. Many of these have since gone extinct or today live in much warmer climates. During the early part of this period, about 35 million years ago, Montana was home to animals like the double-horned rhinoceros-like brontotheres, and primitive little three-toed horses, camels, and deer. In the later part of the time period, 20 million years ago, the valleys hosted bizarre-looking ancestors of our modern elephants, camels, deer, and pigs. These included elephants with shovel-like tusks, deer-like animals with forked horns over their noses, and pigs the size of hippos. Montana was lush and subtropical. The extinction of these groups of animals would coincide with the coming of the Ice Age, and the arrival of humans less than 50,000 years ago.

Where it stands

Worth the stop nearby

• Mai Wah Museum — 22 mi
  Two brick buildings left from Butte's Chinatown, and a store whose goods came home after seventy years away.
• Granite Mountain/Speculator Mine Memorial — 23 mi
  An overlook above the shaft where the 1917 fire began, and the letters some of the trapped men wrote while they waited.

More markers nearby

• The Great Divide Trophy — 10 mi
• Lewis and Clark Expedition — 12 mi
• LaHood Park — 12 mi
• The Jefferson Valley — 16 mi