THK MAYAN CIVILIZATION 125 



lines of evidence capable 4 of being correlated with each 

 other. These arc: — 



1st, Natural developments of sculpture, architecture, 

 etc. 



2nd. Inscribed dates on monuments. 



3rd. Traditional history in the Books of Chilam 

 Balam. 



A fourth important line of evidence remains to be de- 

 veloped in the future. This relates to astronomical 

 time. There is more than a suspicion that the Mayas 

 were able to predict eclipses and there is a strong possi- 

 bility that planetary conjunctions and other calculable 

 phenomena were also recorded. Astronomical checks 

 on chronology may possibly appear after a careful study 

 of the calculations relating to Venus. 



Natural developments in sculpture, etc., validate the 

 contemporaneous and therefore historical character of 

 many inscribed dates. In fact, the relative chronology 

 of the cities of the first great Mayan period, covering 

 over 600 years, is now upon a very certain basis. After 

 the close of this period the dates were no longer in- 

 scribed. We are still able to indicate the course of 

 change in the arts but we cannot express this in terms of 

 years. Finally, in the books of Chilam Balam we have a 

 dependable series of traditions affecting a considerable 

 part of the Mayan nation over a stretch of 1400 years 

 previous to the Spanish Conquest. Now it seems certain 

 that the traditional record overlaps the inscribed record 

 SO far a- definite dating i- concerned while the natural 

 development- give aid and comfort to the simplest and 

 most direct correlation. 



Historical Development of Art. The sequence 



of Mayan monument s can be determined from a study 



of the style of sculpture. Beginning with the human 



