1. Margolis, S. V., and Krinsley, D. H., Nature, 245, 30 (1973).
2. Brown, J. E., Nature, 242, 396 (1973).
3. Margolis, S., and Kennett, J. P., Am. J. Sci., 271, 1 (1971).
4. Margolis, S., thesis, Univ. California (1971).
5. Krinsley, D. H., and Doornkamp, J., Atlas of Quartz Sand Grain Surface Textures (Cambridge University Press, in the press).