WEST THUMB GEYSERS BASIN

West Thumb, South Disturbance Road from the south along the Lewis River meets the big Loop Road. Northeast of West Thumb Junction on the shore of the lake: several geysers, many hot springs colored by microscopic algae, the Thumb Paintpots and Fishing Cone, a crater of a source that stands on the lake waters. Craig Pass (2,518 meters) west, is located on the continental water divide: Little Isa Lake sends the waters from its source to the Pacific and to the Atlantic.

On the southern limits of the lake there are a large number of hot springs, some of which are boiling and others producing the most beautiful clay, resembling a pot of boiling that is projected to a height of 6 to 9 ¾ meters. Clay is white and pink and water seems unfathomable. In other places, pure sulfur is projected in abundance. At times, the soil trembles sharply and then produces an explosion resembling thunder. There are several hundred sources, some along the shoreline, others more indoors and others in the very lake, the size of which varies from mini fountain to wells of 20 ± meters in diameter and deep depth. The water, with pale violet color, is very clear, which makes it possible to discern small objects up to 15 meters below the surface. Another small group presents sources filled with a mud resembling thick paint, different colors ranging from pure white to nuanced shades of yellow, pink, red and violet. At certain times of the day, these sludge are projected to more than 4 meters.