EVIDENCES OF PREVIOUS DENUDATION. 13 



pation of that part of the country in recent times. ; Attalea palms 

 are described as very abundant about the ruins of Copan. in Hondu- 

 ras, which means that the present occupation of the country has con- 

 tinued for a long time. The scarcity of these palms and of wild 

 rubber trees in the neighborhood of the extensive ruins of Palenque. 

 in southern Mexico, would show that this region has not been occu- 

 pied by Indians in recent centuries. History confirms this indication. 

 The great Cortez himself passed close to Palenque on his way to 

 Honduras. Though searching for Indian cities, he found only unin- 

 habited forests and appears not to have learned that the ruins ex- 

 isted. 



PREVIOUS DENUDATION SHOWN BY ABSENCE OE UNDERGROWTH 



PALMS. 



Central America is the home of many species of Chamaedorea and 

 other small palms which live among the undergrowth in the shady 

 depths of the forests. Nevertheless, many localities affording con- 

 ditions apparently suitable for these palms are without any repre- 

 sentatives of the group. The undergrowth palms remain abundant 

 only in regions which have not been completely deforested for agri- 

 cultural purposes, and especially in districts too mountainous and 

 broken for agricultural use. 



Though palms are generally able to grow under a rather wide 

 range of conditions, they can spread only slowly, for their seeds are 

 large and appear to have no ready means of transportation except 

 the wood pigeons, which are exterminated with the forests. Further 

 evidence that the palms spread very slowly is to be found in the 

 fact that nearly all of the native species appear to be quite narrowly 

 localized. The Costa Rican species are not known from Guatemala, 

 nor the Guatemalan species from Mexico, except along the border. 



PREVIOUS DENUDATION SHOWN BY ABSENCE OE HUMUS- 

 INHABITING ARTHROPODS. 



Localities which contain remnants of ancient forests can be recog- 

 nized by the presence of complete faunas of humus-inhabiting forest 

 animals, such as the millipeds and centipeds. and some of the lower 

 orders of insects and arachnids. In districts which are frequently 

 cleared by cutting and burning many of the humus-inhabiting groups 

 are exterminated. Even if they escape the fire they are unable to 

 resist the exposure to the heat, sunlight, and dryness of cultivated 

 lands. As long as the surface soil retains its humus and remains 

 loose and pervious to water some of the smaller subterranean forms 



a Cook. O. F. Culture of the Central American Rubber Tree. Bulletin 19, 

 Bureau of Plant Industry. U. B. Dept. of Agriculture. 1903. 

 145 



