The rule that sedimentation rates decrease as the time interval increases has been examined by a procedure that avoids the mathematical problem of plotting a variable, time, against its inverse. The test confirms that the scaling trend has real physical meaning. In the time range of 10−1–108 yr, sedimentation rates change roughly proportionally to the inverse of the square root of time. This report proposes and evaluates the hypothesis that the growth potential of reefs and carbonate platforms follows the same scaling trend. The trend implies that a growth of 104 µm/yr sustained over 103 yr, an upper limit of reef growth in the Holocene, translates into 102 µm/yr sustained over 107 yr. Decrease of the growth potential with increasing time solves the paradox of drowned platforms if the decrease results largely from environmental factors and not simply from increase of the time fraction of subaerial exposure.