CARBON- It AGE DETERMINATION — F. H. H. ROBERTS 347 



the Mayan and Gregorian calendars has long been a source of dispute 

 and there have been two principal schools of thought in the matter 

 with a difference of about 260 years in the results obtained. Accord- 

 ing to the Goodman-Martinez Hernandez-Thompson correlation the 

 date was June 30, A. D. 741, while in the Spinden correlation it was 

 August 30, A. D. 481. The radiocarbon age based on the average of 

 two runs was 1,470 ±120. The expected result on the basis of the first 

 correlation method should have been 1,210-1,240. For the second it 

 should have been 1,470-1,500. As far as this particular sample is 

 concerned, it appears that the Spinden correlation is the correct one 

 (Kulp et al., 1951). The other object of special interest to many 

 people that was subjected to the carbon-14 method was the Book 

 of Isaiah, the Dead Sea scrolls found in a cave near Ain Fashkha in 

 Palestine. History and tradition placed the age of the book in the 

 first or second century before Christ. The linen wrappings that en- 

 closed the scrolls were used for the radiocarbon sample and gave 

 1,917 ±200 as their age. The scrolls probably are somewhat older and 

 tlie date of their wrappings may well be that of the time when they 

 were cached in the cave. 



The results from carbon 14 as far as geology is concerned are spotty 

 because of the difficulty in obtaining suitable material for testing and 

 because in many instances their stratigraphic position is questionable. 

 However, certain things are apparent from the work done thus far. 

 The dates do fall roughly into the same order as the stratigraphic 

 sequence of the deposits from which the specimens for testing were 

 collected and their relative chronology is acceptable. On the other 

 hand, they are for the most part more recent than many geologists 

 believed would be the case. For example, the Mankato substage of 

 the Wisconsin glaciation is shown to have gotten under way about 

 11,400 years ago with the maximum being reached at approximately 

 11,000. This is somewhat less than half the age previously assumed 

 for the Mankato and if correct will require considerable revision of 

 ideas on the part of some students of geochronology. It is interest- 

 ing to note that radiocarbon dating has confirmed the conclusion, 

 based on pollen studies, that a series of deposits in Germany, England, 

 and Ireland were correlated and belonged to the same interval, the 

 Allerod. Furthermore, they appear to be correlatives of the Two 

 Creeks bog in Wisconsin and to show that there was contemporaneous 

 climatic fluctuation in Europe and North America (Flint, 1951, a, b) . 

 The European dates are: Peat from Wallensen im Hills, northwest 

 Germany, 11,044 ±500; lake mud from Neasham, near Darlington in 

 the extreme north of England, 10,851 ±630; peat from Hawks Tor, 

 Cornwall, England, 9,861 ±500; and lake mud from Knocknacran, 

 County Monaghan, Ireland, 11,3 10 ±720. 



