An Island on the Plains

The panel mentions Cretaceous marine shales in passing; one of them is named for these mountains. In 1903 John Bell Hatcher and Timothy Stanton gave the name Bearpaw to the dark seabed shale exposed around the range's north, east and south borders, and it now covers the same layer from northern Montana into Alberta and Saskatchewan. It settled on the floor of the inland sea roughly 75 million years ago, long before the volcanoes. Near Lethbridge, Alberta, the iridescent shells of its ammonites are dug from open pits and sold as the gemstone ammolite.

Where it stands

Worth the stop nearby

• Decision Point — 25 mi
  The rise where Lewis and Clark spent ten days in 1805 deciding which river was the Missouri, against nearly every man in the party.
• Fort Assinniboine — 27 mi
  The brick border post whose Buffalo Soldiers deported the Cree in 1896, and whose land became the Cree's reservation twenty years later.

More markers nearby

• A Montana Crossroads — 23 mi
• The Manitoba Railroad — 25 mi
• Marias River — 25 mi
• Fort Assinniboine — 27 mi