Excavation was commenced at once in the floor of the chamber. At a depth of 8 inches the hard floor gave place to soft brown sand, which was continuous to a depth of 2 feet, where several small deposits or pockets of lime were found inclosed within it, each of which contained a number of obsidian knives and small cores. The knives were deeply indented on each side of the base, as if to facilitate hafting. The cores, of which 20 were found, were slender and varied from 1 to 3 inches in length. On digging down through an additional 18 inches of the brown sand a layer of lime was exposed about 18 inches in thickness, filling the entire lumen of the chamber, in which were found irregularly scattered 60 cruciform objects, finely chipped in obsidian, each from 3 to 4 inches in length (fig. 31, _a_). These would have served as either arrowheads or small javelin heads, or possibly were intended for ceremonial purposes only. With them were a single pottery vase and two small triangular javelin heads of obsidian. The vase (fig. 31, _b_) was circular in shape, 6 inches in diameter, with a long piglike face protruding from one side. It was made of dark-brownish pottery, painted red and finely polished externally. It was filled with small mussel-like bivalve shells embedded in lime. A number of these shells were found also closely adjacent to the vase in the lime which surrounded it. Beneath the layer of lime lay a layer of brown sand, 3 feet thick, in which absolutely nothing was found. Below this appeared another layer of lime, mixed with sand, 4 feet thick, near the bottom of which were found 40 human skulls, neatly disposed in rows. These, when first uncovered, seemed to be in a moderately good state of preservation, but when removed from their bed of lime and sand they crumbled so easily that it was found impossible to preserve them. The skulls were all placed in the same horizontal plane, each one nearly in contact with its neighbor. No other bones were found with them, or in fact in any other part of this mound, with the exception of two small oblong objects of bone, about 2 inches in length, each still bearing traces of paint, which were discovered among the skulls. These skulls would seem to have been either the result of secondary interments or the remains of sacrificial victims whose bodies were either eaten or buried elsewhere. In favor of the first theory is the fact that the Maya did not practice human sacrifice to anything like the same extent that their neighbors, the Aztecs, did, and slaughter involving forty-odd victims must have been practically unknown among them. Furthermore, in one or two instances small shallow stone-lined graves, covered with large slabs of stone, have been found at and around the bases of large mounds, and it seems quite possible that these graves may have held the bodies of distinguished dead until their skulls were in a fit condition to be removed to the mound or until