CHAPTER XVI. 

 THE SHIFTING OF CLIMATIC ZONES. 



In the preceding chapters we have seen that in few parts of the world is there a greater 

 contrast between the past and the present than in Yucatan and the surrounding regions 

 of Maj-a culture. This is preeminently the case in those districts where magnificent ruins 

 are located in the midst of dense and uninliabitable forests. We have seen further that 

 the ancient Mayas were undoubtedly a remarkabh^ efficient people, in striking contrast to 

 the notable inefficiency of the iiresent inhabitants of the torrid zone and especially of the 

 inhabitants of densely forested areas. Furthermore, according to the overwhelming- 

 evidence of the ruins the Mayan culture developed where we now find its traces, and this 

 development must have demanded many centuries of growth previous to the many centui-ics 

 during which it bore fruition in the great temples and cities whose remnants we now 

 admire. These facts lead to the further conclusion that if the physical conditions of 

 Maya land were the same in the past as in the present, the ancient Mayas, in sharp dis- 

 tinction from their descendants, must have possessed a degree of energy and a power of 

 resistance to the debilitating effects of a tropical climate far in excess of that of any other 

 race now existing. This is certainly a possibihty and can not be lightly dismissed. It is 

 one of those possibilities which can not be proved and which are often adopted as a refuge 

 when all other theories fail. Other possibilities, such as the introduction of culture from 

 the eastern hemisphere or the invasion of Maya land by some alien race possessed of an 

 uncommonly high culture, are more and more being universally negatived by the work of 

 recent scholars. Still another, and (so far as now appears) perhaps the only other genuine 

 possibility is that in the past the climate was so much drier than now that the present 

 forested areas were covered merely with jungle instead of with large trees. Such an assump- 

 tion at first sight appears to be directly opposed to our general conclusion that the south- 

 western United States and central Asia are now on the whole distinctly drier than in the 

 past, but such is by no means the case. Let us first see how much ground there is for 

 believing that climatic changes of any sort have occurred in Yucatan. Then let us investi- 

 gate the probable nature and effects of any such possible changes; and finally let us test 

 all our conclusions by the rigorous method of a comparison of the dates indicated by our 

 California curve and the dates of Maj'a history so far as they have been ascertained. 



Writers on Yucatan have sometimes suggested that the country could not formerly 

 have supported so vast a population had not the rainfall and the agricultural possibilities 

 been greater than at present. Others deny this. They say that an industrious and active 

 people who had the energy and brain-power to construct wells and reservoirs could culti- 

 vate almost every foot of Yucatan proper except for the numerous spots where the bare 

 rock actually comes to the surface. One can ride for days over plains of rich soil, deep, soft, 

 and easy to cultivate, but abandoned to the jungle and to wild beasts. The reason is the 

 difficulty of digging wells or building reservoirs, or else the prevalence of fevers. Except 

 for an insignificant coastal strip where no ruins are found, Merida is as dry as any portion 

 of Yucatan; yet the five months of the rainy season from June to October have 26.5 inches 

 of rain, which is decidedly more than the eastern United States gets during the same period 

 and is sufficient to allow good crops of corn to be raised almost everywhere. That lack of 

 rainfall has nothing to do with the present comparative depopulation of Yucatan is evident 

 enough from the fact that the densest and most progressive population is found in the 



189 



