JOURNSL ROYfiL SOCIETY, N.S.W., 1888. rut. 22. Part 11. 



Fig. 4. Desert Sandstone, Mary River, North Australia, x 70 diam. 



Fig. 5. Ash from Bromo crater, Java, x 70 diam., active volcano 



Fig. 6. Sahara Desert Sand, x 300 dUrn. 



