In regard to the geology it is only necessary to point out a few of the more important characters. The highlands which bear so many active and quiescent volcanoes naturally show great masses of eruptive rocks, some due to recent action and others much more ancient. Porous tufa is a common material for sculptures in many parts of Mexico and Central America. In other places there are great beds of softer and finer grained material also of volcanic origin. In these places, such as Copan in western Honduras and Mitla in southern Mexico, building in stone received its greatest development. The soft greenish stone of Copan seems to be a solidified mud flow permeated with volcanic ash rather than a true lava flow of melted rock. Limestones are also common and important in the economic development. In some regions there are beds of a hard, blue limestone going back to the Carboniferous epoch. This stone makes an excellent cement after burning. The Peninsula of Yucatan is a great plain of limestone of much more recent formation. Like our own Florida it was once a coral reef which was lifted above the sea by some natural agency. This limestone gets older and more solid as we approach the base of the peninsula but at best is rather porous and coarse-grained.
[Illustration: Fig. 3. Yucatan Deer caught in a Snare. From the Mayan Codex, Tro-Cortesianus.]
The fauna and flora present great variation. In the moist lowlands the monkeys play in the tree tops and the jaguar lies in wait for its prey. Alligators and crocodiles infest the rivers and swamps. Two small species of deer and the ocellated turkey are important items in the meat supply of Yucatan, that includes also the iguana, the peccary, and various large rodents. The tapir and manatee are the largest animals of the lowlands but neither seems to have been of great significance to the natives. Bats are frequently represented in the ancient art and a bat demon appears in several myths.
[Illustration: Fig. 4. The Moan Bird, or Yucatan Owl, personified as a Demi-god. Dresden Codex.]
Upon the highlands of Mexico the Toltecan deer is still hunted, together with the wild turkey that is the parent of our domestic birds. The turkey was, in fact, domesticated by the Mexican tribes. It probably occurred southward over the Guatemalan highlands, but is now extinct in this latter region. In the southern part of Central America the place of the turkey as an item of diet is taken by the curassow, a yellow-crested bird with black plumage. The coppery-tailed trogon, the famous quetzal, was sacred in ancient times and is now the emblem of Guatemala. This beautiful bird occurs only in the cloud cap forest zone on the high mountains of southern Mexico and Guatemala. Blue macaws, parrots, paroquets, and humming birds contributed their gay plumage to adorn headdresses and feather-covered cloaks. These and many other birds doubtless flitted about in the aviary of Moctezuma. The black vulture, the king vulture, and the harpy eagle are other conspicuous birds often figured in the ancient art. The coyote, ocelot, and puma are the principal beasts of prey on the highlands.