Starting Point: East end of the parking area
Distances: 0.3 mile, round trip
Topography: A few steep places
Time: 25 minutes
Features: Hydrothermal activity
[Illustration: Trail map]
The name “Sulphur Works” was given to this area when two men, Boarman
and Supan, tried unsuccessfully to develop the sulphur and clay
properties in 1865. The hydrothermal activity consists of hot springs,
mud pots, and fumaroles. As a result of the hydrothermal activity a
number of different minerals are deposited in the area giving it pastel
shades of yellow, orange, green, and red. Some of the minerals found are
powdery opal, chalcedony, hematite, pyrite, kaolinite, alunite, and
sulphur.
It is believed that this is part of the vent system of the ancient
volcano, Mount Tehama, which collapsed thousands of years ago. Signs
posted along the trail explain the various features. This is the only
hydrothermal area close to the park road.
As crusts may be thin with boiling water underneath, visitors are warned
to stay on the trail.
[Illustration: Bumpass Hell]