In answer to Mr. Morgan’s line of argument, it may be said, that the agreement of early voyagers and chroniclers, of whom there is so large a number, as to the main facts, is strong evidence that their impressions, as stated, were founded upon what they saw, and not on pictures of the imagination. Moreover, the existing undecyphered manuscripts, together with the hieroglyphical and symbolical inscriptions upon buildings, traced in characters similar to those found in aboriginal manuscripts, prove that there was a literature among the Mayan and Aztec races, which places them in a grade of civilization far above that of communistic Indian tribes of which we have any record. More than all, the manuscript of Bishop Landa, an eye witness of expiring Mayan civilization, with its detailed account of the political and social relations of the Indians of that country, is strong testimony to the correctness of the generally accepted theories regarding their social and political systems. The truthfulness of Bishop Landa’s account is attested by its conformity to other accounts, and to the customs and usages of the Yucatan Indians of to-day, as described by recent travellers. We are obliged to consider the argument of Mr. Morgan insufficient to destroy the common opinions of three centuries and a half, in so far as relates to the Maya Indians. Mr. Morgan also says that “the Aztecs had no structures comparable with those of Yucatan.” If the only grounds for this statement are, that almost no ruins now remain in that country, and that the early accounts of Spanish writers, of what they themselves saw, are considered, by him, untrustworthy, the weight of probability seems, to the writer of this paper, on the contrary, to lie in quite the other direction. When Cortez left Havana, in 1519, he visited Cozumel, famous for its beautiful temples, and Centla, and certain other towns in Central America, on his way to Mexico. Having thus seen the wonderful structures of Central America, is it not strange, that the historians of that expedition, and Cortez himself, should be filled with wonder and amazement at what they found in Mexico, to a degree that disposed them to give a much more particular account of the Aztec palaces than of Yucatan buildings, if they were inferior to them in point of architecture? Mexico has since that time been more populous than Yucatan, and its ruins have naturally disappeared more rapidly in the construction of modern buildings; but the records of its former civilization exist in the accounts of the discoverers, and in the numerous relics of antiquity contained in the museums of Mexico, and scattered about in the archæological collections of Europe and America. The celebrated calendar stone found buried in the _Plaza Mayor_ of Mexico, and now preserved in that city, demonstrates the astronomical advancement of the Aztecs in an incontrovertible manner, and that monument alone would establish their advanced position.