With reference to this much debated question of the formation of these inclosures, a re-survey of several of them was made. The measurements of Professor Thomas and his assistants appear to have established the fact of the geometrical accuracy of the octagonal, square and circular works near Newark.[99] In the introduction to the memoir upon the Ohio mounds, Professor Thomas observes that “The constantly recurring question ‘Who constructed these works?’ has brought before the public a number of widely different theories, though the one which has been most generally accepted is that they originated with a people long since extinct or driven from the country, who had attained a culture status much in advance of that reached by the aborigines inhabiting the country at the time of its discovery by Europeans. The opinions advanced in this paper, in support of which evidence will be presented, is that the ancient works of the State are due to Indians of several different tribes, and that some at least of the typical works, were built by the ancestors of the modern Cherokees.”[100] As a consequence of the examination of the Indian mounds throughout the United States, the majority of the modern American archæologists consider that the aboriginal inhabitants were never in a higher state of civilisation than they were when they first became known to Europeans. It is not however the questions of the burial mounds, and the importance of what has been found in them which have chiefly to be considered here. Attention should be principally directed to the difficult problem respecting the great fortified ramparts of Fort Ancient. The traditions of the Delawares,[101] which affirmed that the defensive earthworks of Ohio were built by the Tallegwi, have generally been accepted as being well founded. They were stated to have been a powerful tribe who built fortifications and entrenchments. Finally they abandoned their lands and went southwards, down the valley of the Mississippi and never returned. It may be conjectured, after observing the similar works and methods of selecting their defensive positions in Guatemala, that the Tallegwi were the same race who were afterwards known as Toltecs. The probability of this assumption being reasonable, becomes more evident when the group of platform and circular mounds on the plains near Mixco are observed to be similar to those raised on the plains of Cahokia near the banks of the Mississippi. The question of the condition of intelligence amongst the North American Indians, has a direct bearing upon the problem of the origin of the civilisation of the Toltecs and Aztecs, and it is satisfactory to know that there are sound reasons for supposing that the Indians who constructed the fortified camps in Ohio were not more advanced in knowledge than the tribes who were dwelling in that region at the time of the discovery of America by Columbus.