This 37-foot (11-m) hot spring cone marks the northern portion of Mammoth Hot Springs, at the bottom of Lower Terraces. Liberty Cap was named in 1871 by the Hayden Survey party because of its marked resemblance to the peaked caps worn during the French Revolution. Its unusual formation was created by a hot spring whose plumbing remained open and in one location for a long time. Its internal pressure was sufficient to raise the water to a great height, allowing mineral deposits to build continuously for perhaps hundreds of years. Today the cone is no longer active.