About 300 yards to the east of the mound three circular openings were found (see AAA, fig. [26]) leading into a large irregular natural cavity (see C, fig. [26]) formed in the limestone (see BB, fig. [26]). Each of these openings was about 2 feet in diameter, and close to one of them a circular slab of stone, 6 inches in thickness, and of about the same diameter as the opening, was found, which had probably been used as a cover for the latter. This chultun, unlike the first one, was of purely natural formation; the walls, which were rough and irregular, showed no signs of tool marks. The chamber varied in height from 8 to 9 feet beneath the openings, where it was highest, to 2 to 3 feet at the sides. There was a considerable accumulation of earth upon the floor (see DD, fig. [26]), which had evidently fallen and been blown in, as it was collected in two heaps beneath the openings. There were no stone steps leading down into this chultun, and access must have been gained to the interior by means of wooden ladders, which had long since disappeared. Numbers of potsherds, shells, pieces of charcoal, clay beads, and fragments of flint and obsidian implements were found upon the floor. Several skeletons of small mammals were also found among the earth, but these creatures had probably fallen in after the chultun ceased to be used, and had been unable to get out.
At a distance of less than half a mile from the last-mentioned chultun another was discovered under somewhat curious circumstances. A large flat mound was completely removed for the sake of the stone and limestone dust which it contained, to be used in repairing the Corozal streets. About the center of the mound, at the ground level, a heavy circular flag of limestone, 2 feet 4 inches in diameter, was brought to light. On removing this it was found to cover a round well-like opening, which expanded below into a small chultun, 12 feet long by 9 feet in greatest diameter. The chamber was egg-shaped and showed no signs of having ever been stucco-covered. From the opening a short flight of steps, cut in the rock, led to the bottom of the chultun. Nothing was found in this chultun with the exception of two small bowls of rather coarse earthenware, painted red and polished; one almost globular in shape, 6 inches in diameter; the other circular, flat-bottomed, 31/2 inches in height. The mound which covered this chultun appeared to have been one of the commonest kind of burial mounds. At its summit fragments of a rude circular earthenware pot were found, and near its center fragments of human bones, together with three flint hammerstones and two small round vessels, one of light yellow, the other of yellowish-red, pottery.
One of the most remarkable of the chultuns found in this area is situated at San Andres, within a mile of the village of Corozal. It was accidentally found by some coolies in digging marl, and as, unfortunately, the entire roof of the larger chamber and a considerable part of that of the smaller had caved in, it was impossible to discover how it had been entered from outside, as no trace of steps remained. A ground plan of this chultun is shown in figure [27]. The small chamber, A, is 8 feet long, 7 feet broad, and 5 feet 6 inches high in the center; it is cut out of solid rock. The large chamber (C) is 15 feet in diameter, but as nearly the entire roof has fallen in, it is impossible to estimate its exact height. The chambers are partially separated by a wall (B) built of rough blocks of stone and tough mortar, which has been partly broken down. In the side of the small chamber, opposite the wall, are three oblong shafts (D, D, D, fig. [27]) cut into the rock, by the side of the chamber wall, which is here nearly perpendicular. Each of these is about 1 foot in depth by 8 to 9 inches in breadth, and is separated from the chamber by a single row of bricks (E, E, E, fig. [27]) mortared together, reaching from the roof to the floor, so that there is no communication between the shafts and the chamber. Each shaft opened originally on the surface of the ground, but the openings had become blocked by vegetable refuse from the surrounding bush. The bricks which fill in one side of each shaft are of two kinds. The first, by far the more numerous, are made of sun-dried clay, yellowish in color, and very friable: they contain considerable powdered marl. They measure 8 by 4 by 23/4 inches. The bricks of the second kind also are made of clay, mixed with many pebbles; they have been fired, are of a reddish color, far harder and tougher than the first variety; they measure 8 by 4 by 21/4 inches. Nothing was found in either chamber except a few potsherds of various kinds.
Fig. 27.—Ground plan of chultun.
These underground chambers, or chultuns, seem to be fairly common throughout Yucatan. Considerable doubt exists as to the uses to which they were put.[34] It seems probable that those the walls of which were plastered with an impervious cement lining were intended as water receptacles, since they could easily have been filled by drainage from the thatched roofs of buildings in the vicinity, which have long since completely disappeared. Though the southern part of Yucatan, unlike the northern, is fairly well watered, plastered chultuns are not infrequently found there, but always situated at considerable distances from a good permanent water supply, as a lagoon or river. The uncemented chultuns would not hold water, and had probably been used as storehouses for corn and other provisions. Some of these chambers were undoubtedly used as burial places, as one at Platon, on the Old River,[35] was covered by a burial mound, and itself contained human bones; but it is possible that their use for this purpose may have been secondary only. The San Andres chultun is somewhat puzzling, as it was certainly not a reservoir for water, nor were any traces of human burial found within it. It had probably been used as a storehouse for food, though it is difficult to understand the object of the oblong shafts, leading into the open air, found at the side of the smaller chamber, as they must have been quite useless for ventilating purposes, not having any opening into the chamber itself through which the air might circulate.