50 BUREAU OF AMEEICAN ETHNOLOGY [bull. GO 



is equally apparent that the exhaustion naturally and inevitably 

 resulting from the enormous waste of material resources and energy 

 and the inability to sustain the burden imposed by the ruling class 

 is resi)onsible for the downfall, the utter ruin, and hnal abandon- 

 ment of the great Maya cities. The house built on sand must fall, 

 and these and other kindred results of human effort are builded on 

 sands of the imagination. The more rapid the advance and the 

 loftier the rise, the more certain and complete the ruin. 



It is not to be forgotten that various causes, such as change of 

 climate, encroachment of enemies, earthquakes, and other agencies 

 may have contributed to the lamentable result. These, however, 

 were hardly in any case more than contributory agencies. 



