Obsidian Cliff is located about six miles north of Norris Geyser Basin along Highway 89 to Mammoth Hot Springs. Obsidian artifiacts derived from Obsidian Cliff have been found throughout North America. Note the columnar jointing of the two different lava flows preserved in the cliff. The lower obsidian-bearing cliff is an early Quaternary lava flow (called the Obsidian Creek Member of the Plateau Rhyolite). The upper unit in the cliff is the Roaring Mountain Member.
Obsidian forms from rapidly cooling lava that has a very low volitile content (i.e. water, carbon dioxide, etc).
Note that Beaver Pond in the foreground was already overrun with an exotic species, Nuphar polysepalum (yellow pond lilly) when this picture was originally taken, probably in the mid 1880s.