The limitations of my subject do not allow me to do more than mention two other important ruined cities of Yucatan, Izamal and Uxmal. I will however note that, judging from the illustrations I have seen, Uxmal seems to be the “Serpent-city” of America, par excellence, its buildings exhibiting the most elaborate and profuse employment of the serpent for symbolical decoration. One inference from this might be that the serpent was the totemic animal of the ancient builders of this city. The foregoing rapid review of the native chronicles of Yucatan shows that even the foundation of Mayapan was comparatively recent; that the peninsula had, in turn, harbored powerful tribes who had drifted thence from the southwest and Mexican warriors whose aid had been sought by consecutive rulers of Chichen-Itza. We see that Yucatan was the meeting ground for Maya- and Nahuatl-speaking people and that the tendency was to leave the peninsula in search of a more favorable soil and climate as soon as opportunity was afforded. Since the cradle of the Maya civilization is evidently not to be looked for in Yucatan, let us follow the clue afforded by the native traditions, transport ourselves to some of the most important ruined cities of Central America and endeavor to wrest from their monuments some knowledge of the social organization of their ancient inhabitants. In order to institute this search under the most favorable circumstances, I ventured to apply for guidance to Mr. A. P. Maudslay who has made a more thorough, prolonged and extensive study and exploration of these ruined cities than any other person. Upon my request to formulate his opinion as to the respective antiquity and chief characteristics of the most noted sites, this distinguished explorer has most kindly authorized me to publish the following note. “But for a brief note in Nature (28th April, 1892), I have never classified the ruins or attempted to give proofs of differences in age of the monuments, but roughly you may safely class them as follows: I am inclined to look on the Motagua river group as the oldest. The Yucatan group is certainly the youngest. Of course there are many other smaller differences between the groups and much overlapping. Whichever group may be the oldest the art is there already advanced and the decoration has taken forms which must have occupied many kinds of workers to conventionalize from natural objects.” 1. On Motagua River, Quirigua, Copan. Large monolithic stelæ and altars with figures and inscriptions carved on all four sides in rather high relief, some groups pictographic. No weapons of war portrayed in the sculpture. 2. On Usumacinto River, Menché, Tinamit, Palenque, Ixkun. Stelæ are usually flat slabs carved with figures and inscriptions in low relief on one side only. External ornament of the buildings usually moulded in stucco. War-like weapons but very scarce. 3. Tikal. Intermediate between Nos. 2 and 4, but somewhat different and distinct from either.