Figure F16. Close-up photograph of interval 183-1138A-78R-4, 145-151 cm, showing a large ragged pumice clast in a pumice lithic breccia (basement Subunit 2H). Pumice clasts are up to 3 cm diameter but more commonly range from 0.5 cm to 2 cm in size. Almost all pumice clasts show alteration to pale green clay minerals.