•76 BUEEAU OF AMERICAN ETHNOLOGY [bull. 57 



the positions of any number of dates in the Long Count without the 

 use of their corresponding Initial Series. Dates thus recorded are 

 kno^vn as "secondary dates," and the periods which express their 

 distances from other dates of known position in the Long Count, 

 as "distance numbers." A secondary date with its corresponding 

 distance number has been designated a Secondary Series. In the 

 example above given the distance number 3 kins and the date 10 

 Cimi 14 Cumhu would constitute a Secondar}^ Series. 



Here, then, in addition to the Initial Series is a second method, the 

 Secondary Series, by means of which the Maya recorded their dates. 

 The earliest use of a Secondary Series with which the writer is familiar 

 (that on Stela 36 at Piedras Negras) does not occur until some 280 

 years after the first Initial Series. It seems to have been a later 

 development, probably owing its origin to the desire to express more 

 than one date on a single monument. Usually Secondary Series are 

 to be counted from the dates next preceding them in the inscriptions 

 in which they are found, though occasionally they are counted from 

 other dates which may not even be expressed, and which can be 

 ascertained only by counting backward the distance number from 

 its corresponding terminal date. The accuracy of a Secondary series 

 date depends entirely on the fact that it has been counted from an 

 Initial Series, or at least from another Secondary series date, which 

 in turn has been derived from an Initial Series. If either of these 

 contingencies applies to any Secondary series date, it is as accurate 

 a method of fixing a day in the Long Count as though its correspond- 

 ing Initial Series were expressed in full. If, on the other hand, a Sec- 

 ondary series date can not be referred ultimately to an Initial Series 

 or to a date the Initial Series of which is known though it may not be 

 expressed, such a Secondary series date becomes only one of the 

 18,980 dates of the Calendar Round, and will recur at intervals of 

 every 52 years. In other words, its position in the Long Count wUl 

 be unkno^vn. 



Calendak-round Dates 



Dates of the character just described may be called Calendar- 

 round dates, since they are accurate only withm the Calendar Round, 

 or range of 52 years. While accurate enough for the purpose of dis- 

 tinguishing dates in the course of a single lifetime, this method breaks 

 down when used to express dates covering a long period. Witness 

 the chaotic condition of Aztec chronology. The Maya seem to have 

 realized the limitations of this method of dating and did not employ 

 it extensively. It was used chiefly at Yaxchilan on the Usamacintla 

 River, and for this reason the chronology of that city is very much 

 awry, and it is difficult to assign its various dates to their proper 

 positions in the Long Count. 



