Fig. 4: Diagram showing stages of ridge formation and uplift near axis of Rimutaka Range. Duration of beach formation is based on relative cross sectional area of ridges and is given an 10 arbitrary units for C, the largest ridge. It will be seen that the points midway along the times representing ridge formation (still-stand) lie on a straight line that gives the average rate of uplift. The amount of each uplift has been proportional to the total time from the previous to the following uplift, and the time of the next uplift is forecast by the dotted lines in the top right hand corner.