Figure F18. Close-up photograph of interval 183-1139A-53R-2, 51-60 cm, showing the mixed nature of clasts in the silicified basal breccia of basement Subunit 1D. Incorporation of lithic fragments in this interval suggests that the glassy material is not a lava. Minor flow banding is visible in some relatively fresh clasts. The breccia matrix consists of yellow-green to dark green clay.