Lots of geology going on here. Two of my hiking buddies are standing on the remains of a laccolith looking at Lost Lake whose basin was carved by outburst floods during the last ice age. The mountains in the background (Highwoods) are the remains of an ancient volcano that was active 50 mya.
After visiting Lost Lake we hiked up onto Square Butte (another laccolith). Both features are made of rock formed as magma cooled beneath the surface tens of millions of years ago. However, the story of Lost Lake includes another chapter that involved an unusual set of circumstances that happened during the last ice age. To learn how outburst flooding of Glacial Lake Great Falls was involved, go to bigskywalker.com.