The importance of marine bottom-living communities as a controlling factor in much limestone accumulation is urged. This control, largely occult due to subsequent events, must be considered in reconstructions of the conditions of deposition. If an abundant benthos is considered normal for much limestone accumulation this could have significant hydrodynamic effects on the sediments being formed. Altered interpretation of the conditions of deposition could assist exploration thinking. More detailed stratigraphic analysis of limestones will be highly rewarding both geologically and economically.