discoverers of Luray Caverns entered. Luray Caverns does not date beyond the Tertiary period. The cave is developed in dolomites of the lower Beekmantown Dolomite (Lower Ordovician). At some period, niches and already formed chambers were completely filled with water, highly charged with acid, which then slowly began to eat away at much of the softer material composing much of the walls, ceilings and floors. The one particular area that shows this high level of water is Elfin Ramble where water marks of oscillation are highly visible on the ceiling. The temperature inside the caverns is uniformly , comparable to that of Mammoth Cave in Kentucky. Speleothem formation As with other limestone or "solution" caves, formations at Luray Caverns result from a solution of calcium carbonate giving up some of its carbon dioxide, thus allowing a precipitation of lime to form. This precipitation begins as a thin deposit ring of crystallized calcite, but continues to collect, creating stalactites and other types of dripstone and flowstone. Formations at Luray Caverns are white in color if the calcium carbonate is in its pure form. Other colors reflect impurities in the calcite resulting from elements absorbed from the soil or rock layers: Reds and yellows due to iron and iron-stained clays; black from manganese dioxide; blues and greens from solutions of copper compounds. Luray Caverns remains an active cave where new formation deposits accumulate at the rate of about every 120 years. Celebrated speleothems After the water had been mostly removed by a lowering in the water table, these eroded forms remained and growth began to take hold via stalactites, stalagmites, columns, etc. Some notable formations include the Leaning Column, undermined and tilting like the campanile of Pisa; The Great Stalacpipe Organ, a large shield formation, that was used from very early on as an instrument for a variety of folk and religious songs; and a vast bed of disintegrated carbonates left by the water in its retreat through the great space called the Elfin Ramble. The cavern is yellow, brown or red because of water, chemicals and minerals. The new stalactites growing from the old, and made of hard carbonates that had already once been used, are usually white as snow though often pink or amber-colored. The Empress Column is a stalagmite high, rose-colored, and elaborately draped. The Double Column, named from Professors Henry and Baird, is made of two fluted pillars