Figure 4. Comparison of radiometric dates of Caribbean tephra layers and the Neogene biostratigraphic ages correlated to the Berggren et al. (1995a) time scale. The black circles show calibration ages used in the Berggren et al. (1995b) age model. The ⁴⁰Ar/³⁹Ar ages are shown with 2- error bars. Data are presented in Table 2. Ma* = ages of magnetic reversals for Subchron C3n.4n(o) and younger have been calibrated to the astronomical time scale of Shackleton et al. (1990), Hilgen (1991), Langereis et al. (1994), and Berggren et al. (1995a).