Black Chasm was likely known about by the local Miwok tribes, though gold miners were the first credited with exploring the cave in 1854. The miners described the cave as having "...vaulted chamber[s] large enough to contain the largest trees..." and "... crystals [that] stood out from the walls in every conceivable direction, turning and bending into many shapes...". These turning and bending formations are known as helictites and are an unusual formation in cave systems throughout the world. Somewhere near the 1860s, the cave entrance was enlarged from its original 18" wide crack in order to accommodate stairs for tours. The tours lasted only a short time before the cave was abandoned.