In the beautiful Catacombs progress is as slow as in a cactus thicket or a blackberry patch. The crevices lack none of the usual crevice irregularities; high places must be mounted or descended, chasms crossed and narrow passages crawled through, while extra caution must be exercised to avoid striking the head or making a misstep that might result in a fall. The hands are in constant use and soon become so sensitive that holding a soft handkerchief gives infinite relief; but the worst experience is the "crawls" where only the soles of the feet, being temporarily turned up, seem safe from the savage treatment of the sharp calcite dog-teeth. The worst crawl encountered was a small one having a downward slope with a jump-off at the end which necessitated its being taken feet first. Fortunately it was short. But in no place do the difficulties outweigh the pleasure of beholding scenes of such beauty, or suggest regret for the time, torn garments, and personal exertion required for its enjoyment.
In many portions of the cave the surface layer of crystals has had the points worn away by the action of water, later than that in which they were formed; but in the Catacombs and other extensive regions as well, the finished work of crystallization is preserved in an absolutely perfect condition. And everywhere the largest crystals are on the under side of a projection or the roof of a cavity.
As the day was passing far too rapidly and many points of special interest yet remained unseen, we turned with reluctance from the beauty and relief from the hardships of exploration in the Catacombs, and made our way over a crevice into Santa Claus' Pass, which was traversed for a considerable distance and then abandoned for a low crawl terminating at the Senate Chamber. This is a large room extending to Poverty Flat, and is brilliantly red and purely white, most of the crystal presenting a smooth surface. Under the Senate Chamber there is said to be some fine box work which we had no time to visit. The name of this chamber was given by a visiting party composed of members of both houses of Congress. A smaller room, which is really an extension of the Senate Chamber, has handsome walls of white and red box work on account of which the same distinguished party called it the Senate Post-office.
From here a difficult crawl, through red rock, well-worn by the action of water, leads to the Starr Chamber, another large room in white and red, and named by Senator Starr of South Dakota.
Opening out from the last room is a curious, dangerous looking, narrow, crevice-chamber known as Suicide Room on account of the threatening appearance of over-hanging rocks, some of which have at times fallen in great masses of various sizes to form an irregular floor; and a descent of this is necessary in order to reach a short and extremely rough crawl, beautifully and painfully decorated with sharp crystals above and below and on the sides. From this we emerge into Rainy Chamber, an elliptical room not less than two hundred feet long by one hundred feet wide, with a tent-like ceiling rising high in the center and sloping down to meet the floor, which also slopes irregularly toward a deep central depression, giving the room a greater height than any other visited. The high points are generally seen in the narrow crevices, while the rooms of generous length and breadth are usually low, many of the largest having an average of five feet or even less.
Although there is frequent intersection of crevices, and each chamber has passages leading out on every side, the general direction of the cave is said to be northwest-southeast.
Rainy Chamber is named from the fact that during the early months of summer water falls constantly in the form of a light shower; but it drips at all times, and in consequence there is an opportunity to study the active process of formation of one of the deposits which is very abundant in Wind Cave and considered the most perplexing. This is the pop-corn, and the theories of its origin have been steadily rejected at Wind Cave because of a doubt being entertained as to whether it has been deposited under water or by drippings. Here in Rainy Chamber it is fully explained. Near the center of the room the fallen masses are heavily crystallized, much of the groundwork being fine box work and the crystals in perfect condition. On these crystals the pop-corn is being formed, and specimens can be seen in all stages of development, from the beginning to an approximate degree of finish; and whatever the position it occupies on the receiving surface, either on top, underneath, or on a side exposure, it always maintains the same relative position as growing plants on the mundane sphere. The water falling on the upper surface in scattering drops forms myriads of minute stalagmites; on side positions the falling drop first strikes the point exposed to its line of descent and then spreads. The scant moisture slowly makes its way down sloping sides and shelving edges, leaving on each small irregularity a tiny portion of its volume, to deposit an infinitely small charge of solid substance, and the balance finally hangs in moisture less than drops on the growing grains of the under surface.
Pop-corn, therefore, is the globular aragonite of the stalagmitic variety. A small specimen from Rainy Chamber, placed beside one of the same color from Wind Cave, shows them to be absolutely alike.
Rainy Chamber is the room in which the bones of the three-toed horse, already referred to, were found, but their presence has not yet been explained; therefore the case is open to conjecture and several theories may be advanced and their values considered. The first question when such a discovery is made, is whether the living animal was possibly a cave-dweller; which, as the horse was not, is quickly disposed of and attention turned to the next, the possibility of a carniverous animal having carried his prey into the dark recesses of the cave in order that the enjoyment of his dinner might be undisturbed. This theory is equally unavailable by reason of the topographical features presented. If the present natural entrance to the cave were the only way into this room from the outside, the distance was too great and beset with many difficulties; besides which the final passage is too small to admit an animal of sufficient size to carry any considerable portion of even a very small horse. But if at that period the room had direct communication with the outside through an opening since closed, the shape of the walls indicate that it must have been a pot-hole in the roof, and through this an animal could have entered by falling, which the horse and others may have done. But it seems most probable that the remains were carried in by the water through such a hole before it was closed at the beginning of the Quaternary period, when the erosion of the Hills was most active.
Rainy Chamber also contains a large and beautiful assortment of the small polished and coated pebbles called cave pearls.