National Geographic : 1964 Jun
Gypsum flower adorns an Ozark cave in Arkansas; sil ver dollar shows scale. Of pencil thickness and five inches long, the flower could be marred by a touch. "It is as fragile as a peppermint stick," says photographer Earl Neller. Gypsum flowers sprout from walls, ledges, and ceilings, their crystals ex truding through porous rock like toothpaste from a tube. Helictites wreathe a five foot archway in the Caverns of Sonora, Texas. To guard against falling rock, Scott Moore wears a hard hat with carbide lamp. Helictites grow by the millions here. For years the discoverers kept the cave secret to pro tect its bizarre formations. Snake-dance helictite, since collapsed, thrusts 21/2 feet of crystal growth from a sheet of flowstone in the Caverns of Sonora. A tiny tube is thought to carry min eral-laden water from the helictite's base to its ex treme end, where calcite is deposited. Changes in air flow, climate, and chemicals determine the erratic shape. Needles of gypsum so frag ile that they break under their own weight grow in lovely disarray in Fitton Cave, Arkansas.