“…Their discussion is extremel y l ucid and wel l worth reading over 30 years l ater. One aspect that led to some controversy fol l owing the original publ ication is their cal cul ation of the force exerted by a pore fluid on a porous sol id (Laubscher 1960, Moore 1961, Hubbert & Rubey 1960, 1961. This is a subtl e issue that has been overl ooked in previous critical taper anal yses, and we address it in some detail here.…”