Travel Reference
In-Depth Information
Obsidian Cliff and Beaver Lake as they appeared a century ago.
Don't be disappointed when you can't see your reflection in the rock of the cliff across the
road! Not only are the purest bits of obsidian far from the road, but also the Obsidian Cliff
that Haynes saw has probably changed, because many early visitors chopped of bits of the
cliff as souvenirs and because moss and lichens have thrived on the rock, covering up much
of its shine.
12.4/8.6
Unmarked turnoff on west for Obsidian Cliff exhibit.
Obsidian Cliff,
became a
National Historic Landmark in 1996 for its importance as a prehistoric site. Obsidian is a
black or dark-colored volcanic glass that commonly forms on the margins of rhyolitic lava
flows. Obsidian Cliff, composed largely of glass, is the western edge of a huge mass of lava that
flowed and cooled here about 180,000 years ago, long after the last major Yellowstone caldera
event (639,000 years ago).
