In confirmation of this, there was found on Sandy Island, a vast burying ground and "a multitude of human bones was discovered." This traditional testimony has been in many instances confirmed by unmistakable traces of a terrible conflict throughout the Ohio Valley. The story of these bloody battles, handed down for generations, very probably caused the Indians to name this place the "Dark and Bloody Ground." Believing it to be filled with ghosts of its primitive people, it is no small wonder that this race, full of imagination and superstition, should use it so little as a permanent home. But who was this primitive race? Whence did they come and what did they accomplish? The works they built have lived after them, and from these silent memorials the people have been called Mound Builders. Beyond the bounds of memory, into the land of mystery we go when we strive to learn of them. They have left their imprint in the valleys of the Licking, the Kentucky, the Ohio, and the Cumberland. Their many mounds vary in size, shape, structure, location, contents, and use. Some cover only a small area, while others have a diameter of over one hundred feet and one covers fifteen acres. They display a considerable knowledge of geometry, engineering, and military skill. Because some have supposed these ancient people to have been sun worshipers, the "high places" for ceremonial worship are called temple mounds. The fact that these are more numerous in Kentucky than elsewhere, may have given rise to the expressions "sacred soil" or "God's country." Within or near these inclosures are mounds containing altars of stone or burned clay, known as altar mounds; the burial places, called mounds of sepulture, are isolated and contain human remains which shed more light on the character and achievements of this prehistoric race than any others. The military mounds, or works of defense, are usually near a waterway, often on a precipitous height, in a commanding position, and with an extension ditch or moat; the skill, the foresight, and the complete system shown by these would prove that there were fierce foes to be resisted and a vast population to be defended.