No well considered theory of these ruins can avoid the conclusion that most of them are very ancient, and that, to find the origin of the civilization they represent, we must go far back into the “deeps of antiquity.” On all the fields of desolation where they exist, every thing perishable has disappeared. Wooden lintels are mentioned, but these can hardly be regarded as constituting an exception when the character of the wood, and the circumstances that contributed to their preservation, are considered. Moreover, wooden lintels seem to have been peculiar to Yucatan, where many of the great edifices were constructed in the later times, and some of them of perishable materials. Every where in the older ruins, nothing remains but the artificial mounds and foundations of earth, the stone, the cement, the stucco hard as marble, and other imperishable materials used by the builders. If the edifices had all been made of wood, there would now be nothing to show us that the older cities had ever existed. Every trace of them would have been obliterated long before our time, and most of them would have disappeared entirely long before the country was seen by the Spaniards. The places where they stood, with no relics save the mounds and pyramidal platforms, would resemble the works of our Mound-Builders, and not a few “sound historical critics” would consider it in the highest degree absurd to suggest that cities with such structures have ever existed there. Under the circumstances supposed, how wisely skepticism could talk against a suggestion of this kind at Copan, Mitla, or Palenque! and how difficult it would be to find a satisfactory answer to its reasonings! Nevertheless, those mysterious structures have not wholly disappeared, and we can easily understand that there was a time when large areas connected with them were covered with buildings of a less durable character.