In September 1949 I presented a short paper at the International Congress of Americanists in which I claimed that the calendar outlined in the first 14 pages of the Book of Chilam Balam of Tizimin corroborated my correlation between the Maya and Christian timecounts. The new correlation,'derived from astronomical data in the Dresden Codex, equates 13.0.0.0.0 to B. C. 3374 March 10 Julian. Spinden's “Ahau Equation” places the basic date 246 days later, whereas the Goodman-Thompson correlation places it 260 years later, at B. C. 3114 September 7. At the close of the paper, Mr. Linton Satterthwaite, Jr. kindly remarked that archaeologists would reserve judgment until a translation of the Book of Chilam Balam of Tizimin was published.