Kootenai Falls - The trail to the Kootenai Falls is accessed from the trailhead on Highway 2 located between Libby and Troy. This short hike into the river canyon offers some interesting exposures of geologic features which are part of the Mount Shields formation of the Belt Supergroup. These features include ripple marks, salt casts, mudcracks, and fossil stromatolites. The stromatolite bed located near the footbridge over the Kootenai River is composed of vertically stacked “heads” of fossilized algae which are 12 to 24 inches wide and more than 3 feet high.