Local surface density Σ₆ as a function of the mass of the clump for the central subregion of NGC 2264 (panel a, black markers) and in the northern and southern subregions (panel b, red and blue markers, respectively). The potential correlation between Σ₆ and M in a, Σ₆∝ M^0.47 is represented by a dashed blue line in both panels a and b. Completeness levels are indicated by dotted vertical lines.