  We consider the cross correlations of low-lying energy levels of nuclei
belonging to small intervals of the excitation-energy ratio R_{4/2} of the
first 4^+ to 2^+ states. The mean value of the cross-correlation coefficients,
plotted as a function of R_{4/2} has deep minima at values of R_{4/2}=2.2 and
2.9, which correspond to the critical dynamical symmetries of the interacting
Boson model. The distribution of the calculated coefficients for nuclei
belonging to different R_{4/2} classes has different pattern.
