Mammoth Hot Springs are the main attraction of the Mammoth District. These features are quite different from thermal areas elsewhere in the park. Travertine formations grow much more rapidly than sinter formations due to the softer nature of limestone. As hot water rises through limestone, large quantities of rock are dissolved by the hot water, and a white chalky mineral is deposited on the surface.
Although visitors are sometimes confused by the rapidly shifting activity of the hot springs and disappointed when a favorite spring appears to have "died," it is important to realize that the location of springs and the rate of flow changes daily, that "on-again-off-again" is the rule, and that the overall volume of water discharged by all of the springs fluctuates little.