Term Definition
Ashley et al. 1933

Ashley, G. H., M. G. Cheney, J. J. Galloway, C. N. Gould, C. J. Hares, B. F. Howell, A. X. Levorsen, H. D. Miser, R. C. Moore, J. B. Reeside Jr., W. W. Rubey, T. W. Stanton, G. W. Stose, and W. H. Twenhofel. 1933. “Classification and Nomenclature of Rock Units.” Bulletin of the Geological Society of America 44: 423–59.