INTRODUCTION 19 
The Island of Ometepec in Lake Nicaragua bears an 
active volcano. 
In regard to the geology it is only necessary to point 
out a few of the more important characters. The high- 
lands 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 voleanic origin. In these places, such as Copan in 
western Honduras and Mitla in southern Mexico, build- 
ing 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. 
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 low- 
lands but neither seems to have been of great signifi- 
