Description: From Jicha and Singer: "The western flank of the cone and southern margin of the rcv flow are overlain by a small, gray, vitrophyric lava flow (srf), the most evolved on the island (71.4 wt% SiO2) (Table 2; Fig. 4 [in original text]). The 40Ar/39Ar geochronology was unsuccessful on this material, but whole-rock, plagioclase, clinopyroxene, magnetite, and glass yielded a U-Th isochron age of 6+/-4 ka (Jicha and others, 2005)."