While cemeteries of this character are known to have extended over wide areas of lowland, stone graves were also built into low pyramids by placing one tier on top of another until from four to six had been laid. Each tier as completed--probably each grave as added--would be covered with earth, so that the whole formed a burial-mound fifty feet or more in diameter and eight or ten feet high (the bottom tier of graves being sunken), containing perhaps two hundred bodies. Not only within the cysts, but on and around the stones throughout the mound, were exhumed many relics, especially of pottery, showing that food and offerings had been laid upon the graves after they were closed. Nowhere was there the least indication of any contact with Europeans; and these cemeteries undoubtedly antedate the coming of the whites. Among the most strikingly interesting discoveries made during the past few years is the burial-place in the Miami valley of Ohio, with its hundreds of singular pits dug in the hard clay below the leaf-mould in which the skeletons are found. This place was discovered by the members of the Madisonville Literary and Scientific Society, which, during three or four years, carried on an exploration under the personal direction of Dr. C. L. Metz. In 1880 the Peabody Museum was invited to join in the exploration, and Professor Putnam visited the locality soon afterward. The result of this co-operation is apparent in the large collections brought to the museum, where the contents of several of these strange pits are shown, as well as thousands of objects obtained from others or occurring with the skeletons in the leaf-mould. More than fifteen hundred pits and a thousand skeletons have now been uncovered and examined, several acres having been dug over, foot by foot, with painstaking completeness. The pits, hollowed out of the underlying clay, are from two to seven feet in depth, and about four feet in diameter, hidden under a stratum of slowly-accumulated leaf-mould two feet thick. The majority of them, evidently, had been made previous to the burial of the bodies, though some were more recent than a few of the graves. The labor expended in digging them, and the peculiar character of their contents, render it not improbable that they were made in pursuance of some superstition or as part of a religious rite. This is an unsatisfactory generality, but more cannot yet be said with safety.