Many of these mounds, from their shapes, it is thought, were used for fortifications, and sometimes they are at regular spaces apart, which shows they may have been used for sending signals across the country. They were made almost entirely of earth, but sometimes brick and stone were used. Sometimes they were built very high, and on the tops of these highest mounds have been found pieces of burned wood, showing that they were probably used as places of worship, and that the priests offered up burnt-offerings and sacrifices there. The mounds are sometimes in the form of animals and men. In those that were used as places of worship human bones have been found, and with them many things which show that the Mound-builders must have known some of the arts which the tribes who lived in America at the time of its discovery by the Europeans knew nothing of; among these things are carvings in stone, pottery, articles of ornament in metal, silver and copper tools, such as axes, chisels, and knives, beside beads, bracelets, carved pipes, models in clay of birds, quadrupeds, and human faces, etc. Is it not strange to think of this race of people who lived here in our own America so many years ago? We would like to know how they lived, what they looked like, and what language they spoke, but we cannot even guess. We only know that ages after the time of the Mammoth and Mastodon, this curious race, coming doubtless from the East, entered the Mississippi Valley; that they settled there and built those wonderful mounds at least two thousand years ago, if not longer; that finally they disappeared, and we should never have known of them but for the works they have left. CHAPTER III. THE RED MEN.