Lower Geyser Basin which has a much less concentrated set of geothermal features, including Fountain Paint Pots. Fountain Paint Pots are mud pots, that is, a hot spring that contains boiling mud instead of water. The mud is produced by a higher acidity in the water which enables the spring to dissolve surrounding minerals to create an opaque, usually grey, mud. Also found in this basin is Great Fountain Geyser, whose eruptions reach 100 to 200 feet (30–61 m) in the air, while waves of water cascade down its sinter terraces.