CLIMATIC CHANGES AND MAYA HISTORY. 



231 



dates are, of course, only approximate. They are given according to Bowditch's system. 

 Figure 72 is repeated in order that it may be available for direct comparison with the table. 

 No great weight must be attached to the general agreement which this table seems to 

 show between climatic pulsations and the history of the Mayas. In the first place, the 

 agreement does not apply to details, and in all probability no amount of investigation is 

 ever likely to show that it does so apply. In the second place, so long as Mayan chronology 

 is so uncertain we can not lay much weight upon it. The chief reason for introducing the 

 matter is to point out one of the ways in which the study of climate may cooperate with 

 archeolog}'" and history, and each may be used as a check upon the other. In the coui'se of 



Table 12. 



Period. 



Date. 



Inferred climatic conditions in Maya land. 



1000-400 B.C. 

 400-100 B. c. 



100 B. C.-300 A. D. 



300-450 A.. D. 



450-900 A. D. 

 900-1100 A. D. 



1100-1300 A. D. 



1300-1450 A. D. 

 1450-1900 A. D. 



Pronounced dry winter season everywhere, strong 

 I contrast of seasons, few dense forests, conditions 

 much more stimulating than now. 

 Similar to (1) but not quite so strong a contrast of 

 j seasons. 

 Intermediate between (I) and (2), but beginning to 

 become less favorable toward the end of the period, 

 ! especially in the south. 



Steady increase of unfavorable conditions. The dry 

 ; season must have largely disappeared in the south 

 and dense forests must have tended to appear when- 

 ever cultivation was relaxed. 



Highly unfavorable conditions, part of the time no 

 better than those of to-day and at times worse. 

 Forests probably prevailed everywhere except in 

 the narrow strip of northern Yucatan. 



Partial return to favorable conditions of early periods, 

 but not enough to influence the southern part of 

 Maya land. 



Return to unfavorable conditions about like those of 

 to-day. 



Second partial return to favorable conditions, like' 



(6), but not quite so favorable. 

 General continuance of unfavorable conditions. 



Historical conditions in Maya land. 



Period of developing culture and great progress. 



Period of first known artistic work. Not essen- 

 tially different from (1). 



Period of high culture beginning in the south and 

 progressing northward. By the end of the 

 period great architectural works had ceased in 

 the south but not in the center. 



Extinction or great decline of southern civiliza- 

 tion. The center of activity moved to northern 

 Yucatan, where it is now located; but there is 

 no evidence of any such state of activity as had 

 formerly prevailed in the south. 



The Dark Ages of Maya history. Civilization at 

 a low ebb. No evidence of any great archi- 

 tectural or other activity. 



Pronounced revival of culture, great architectural 

 and other activities, but only in northern 

 Yucatan, that is, in the present dry area and 

 its immediate neighborhood. 



Renewed decline of civilization. Frequent wars 

 and invasions. End of the era of building; 

 abandonment of great cities. 



Continued decline of civiUzation, no evidence of 

 any genuine recovery. 



Persistent continuance of native civilization at a 

 level which is not especially low compared with 

 other lands within the tropics, but is very low 

 and unprogressive compared with the great 

 eras of the past. 



B. C. A. D. 100 



^00 



3C0 



Fig. 72.^Changes of Climate in California for 2,000 Years. 



This figure is the same as the part of figure 50 after 100 b. c, but is plotted with a three-fold greater vertical scale. 



time, when the ruins of Maya land have been thoroughly explored and excavated, it will 

 doubtless be possible to frame an exact chronology, and to determine the sequence of the 

 main events in Maya history. The doing of this will have no bearing upon conclusions 

 resting on such evidence as the trees in California, but it will prove an admirable test of 

 the portion of our theory involving the relationship of climatic changes to lands within the 

 tropics, and to the history of civilization in that region. 



Meanwhile let us sum up the net results of our entire study of climatic changes, whether 

 in Arizona, New Mexico, California, Mexico, Yucatan, or Guatemala. The main signifi- 

 cance of the whole matter Ues in the fact that from a long and complex chain of reasoning, 



