Arizona Radiocarbon Dates VIII

The carbon isotopic analyses reported here covers the period since the last list (Haynes et al. , 1967) until summer 1969. All results relating to secular C 14 fluctuations in atmospheric CO 2 are now published separately (Damon et al. , 1970). Sample preparation and counting procedures remain essentially unchanged since completion of our conversion to CO 2 in 1960. All δ C 13 values are reported relative to PDB and all C 14 dates, unless otherwise noted, are based on the 5568 year half-life, but are not corrected for C 13 content. 0.95 NBS oxalic acid activity is our routine standard periodically monitored for isotopic fractionation.