Complying with; thus, accordant drainage has evolved in conformity with the underlying geological structure: domes show a radial pattern, for example. The law of accordant junctions (Playfair’s law) states that tributaries join a stream or river at the same elevation as that of the larger watercourse; there is no sudden ‘drop’ in the level of the tributary, which is therefore graded to the level of the junction. See Niemann et al. (2001) ESPL 26, 12 for a quantitative evaluation of Playfair’s law. Accordant summits are hill or mountain tops of approximately the same elevation, whose presence has been seen as confirmation of the cycle of erosion theory (Ojany (1978) Geo. J. 2, 5).