Figure F20. A. Photomicrograph showing the zeolite stilbite as a cavity filling in Section 205-1253A-33R-1, in lower part of Subunit 4B. B. Vein up to 0.5 cm wide filled with pale green clay in interval 205-1253A-42R-2, 72–101 cm. The interior of the vein shows a lighter color, which could be zeolites. The sample in B was taken for microbiological studies at the interval immediately adjacent to the bottom of part B. pl = plagioclase.