Figure 2. Hamblin's nomenclature for dams and volcanic stratigraphy and the inferred relative ages of each dam, based largely on inset relationships (Hamblin, 1994). The ⁴⁰K/⁴⁰Ar dates are in gray from Dalrymple and Hamblin (1998). New ⁴⁰Ar/³⁹Ar dates (see Table 1 for references) do not substantiate the proposed age sequence.