SEQUOIA Crystal Cave in Sequoia National Park

Just inside the cave the stream is concealed under a ledge in a clean "U" shaped marble trench about six and a half feet deep and two feet wide, which gradually grades up to the level of the floor 160 feet from the entrance where it first comes into view at the foot bridge. Here it makes two almost right angle turns in adjusting itself from the west to the east side of the cave and follows beside the trail for an additional 75 feet, where it recrosses to the east side of the cave beneath another bridge. A short distance above this point, the stream disappears under a ledge and flows slowly over a light gravel fill through a low chamber about two and a half feet high and twelve feet wide. Here again a beautiful profusion of stalactites are forming directly above the sluggish stream, partly impounded on the level floor. The stream reappears in the Junction Room five hundred feet from the entrance and finally disappears beneath the stone floor of the second level of the cave about 100 feet beyond the Junction Room.

The cave stream has special significance. Some think that it has been the principal agent in the excavation of the cave, while others contend that it is secondary and that it has only modified and enlarged selected parts of pre-existing chambers and passageways that are of suitable grade, which the stream could follow most easily.

The stream today is enlarging and modifying the cave in two ways. Near the entrance it is eating its way deeper into the marble trench in its attempt to maintain grade with the parent Cascade Creek on the outside. The trench is slowly migrating headward into the cave as the base-leveling process continues. A short distance above the trench where the stream flows sluggishly on grade over the almost level, gravel-covered floor, it cannot deepen its channel but is slowly dissolving the marble laterally. After many thousands of years, the stream will be rejuvenated in this section of the cave as the trench is extended upstream, thus increasing its velocity and cutting power.

It has been noted that the cave became substantially filled with clay, sand and gravel by a larger depositing stream after the major galleries had been mostly dissolved out, and that subsequently this fill has been removed largely as the stream load was reduced and its transporting power increased. Armed with particles of sand and gravel, the stream was able by abrasion to enlarge and modify those parts of the cave through which it flows, as well as by dissolving the marble. Evidence of stream work is preserved on the walls and ceilings in many parts of the main passageways. After most of the fill had been removed, the stream appears to have lost much of its volume and transporting power, until reduced to its present state in which its dissolving power is dominant over abrasion. Even in the rather steep marble trench where the stream flows rapidly, the principal process seems to be that of dissolving the marble rather than wearing it mechanically, as there are thin, blade-like dikes of insoluble material extending across the channel. Some of these are almost knife-edge sharp and could not have resisted much mechanical wear. They stand out from the marble because they are less soluble.

Examples of stalactites, stalagmites, columns and rimstones basins in the Junction Room.

In no part of its known course is the present stream accomplishing work that could conceivably result in duplicating the major complex features of Crystal Cave. It appears to be following a pre-determined course which it is modifying as noted previously, in the base-leveling process.

In addition to the difficulty of explaining the origin of many solution features in the cave and the amazing complexity of its intricate ground plan on the basis of stream wear, it seems reasonable to expect that the largest rooms would occur near the entrance where the volume of water would be greatest, and that the openings would become progressively smaller away from the entrance as the stream branched out, if the system had been excavated in this manner. Such is not the case, for the cave narrows down to three feet in width by ten feet high, with a communicating low chamber two and one-half feet high and twelve feet wide 400 feet inside. The largest room in the cave is most distant from the entrance and is known to have had a height of at least 75 feet before the collapse of marble occurred. Its average width of more than 50 feet, and a length of about 140 feet, dwarfs the dimensions of the entrance room which is separated from the major large rooms by the restricted portion of the main passage mentioned previously. This discrepancy in size can scarcely be explained on the basis of variable resistance in the rock structure.

Perhaps there are other caverns dissolved in marble beneath Crystal Cave waiting for surface streams to cut to their horizon and drain them, thus duplicating the higher features of the underground landscape, which in time will hasten the lowering of the land as Crystal Cave ridge is gradually reduced in the general base leveling process.

A scene in the Organ Room. Note curved, double-edged stalactites.