Figure 4. Photomicrographs of plagioclase phenocrysts from a basalt clast from interval 149-899B-27R-1, 19-26 cm, in cross polarized light (XLP). The long dimension of the photomicrographs is approximately 2.7 mm. Figure 4A shows a euhedral crystal outline and altered interior of a zoned plagioclase phenocryst. Figure 4B shows several plagioclase phenocrysts of varying size.