centuries after they were driven by their enemies from the country north of the mouths of the Missouri and Ohio Rivers. The condition of skeletons found in the mounds indicate an antiquity which they furnish us no means of measuring. It is not to be presumed that all human remains discovered in excavating the works were interred immediately previous to the abandonment of the country. Some of them may belong to the middle or beginning of the period of their residence in the territory occupied by the United States. Human remains taken from the mounds, perhaps furnish us better evidence of the long residence of the Mound-builders in this country than any other data in our possession. It suffices to say that few Mound-builder crania have been recovered in a condition to be of any service to science; although of late years, several valuable collections have been made. The preservation of the skeletons depends greatly on the composition of the soil in which they are found. The Loess has afforded well-preserved remains, however, with the gelatinous matter leached out. The crania of the sandy loam of river bottoms, on the other hand, are in all cases so far decayed upon discovery that the greatest precautions fail to prevent them from crumbling to dust when exposed to the light and air. Mastodon bones, on the contrary, recovered from peat swamps, and much older than any of the remains of the Mound-builders, are found to have retained so much of their gelatinous matter as to furnish a nourishing soup.[93] To these evidences may be added the testimony derived from the ancient ruins which points to long-continued occupation and to a considerable lapse of time since their abandonment.