This image provides a closer look at the gypsum "snowballs" on the ceiling of the Snowball Room. The seawater of the ancient seaway where the lime mud (that eventually became limestone) was probably saturated with the ions of calcium and sulfate. As a result some the mineral gypsum (CaS04-2H20) was trapped in the microporous spaces within the limestone. Once this section of the cavern became dry, traces of calcium-sulfate-rich water migrated from the limestone to the cave ceiling, resulting in the gradual formation of gypsum crystal masses.