Superdeformed bands at high spin in Z=66 and 68 isotopes.

The nucleus /sup 152/Dy, with sharp ridges in the ..gamma..-..gamma.. energy correlation matrix, stands out from three neighboring nuclei which exhibit less pronounced structures. The ridges include the observed discrete superdeformed band, but must be composed mainly of unresolved superdeformed bands, which decay predominantly to less deformed states. A simple decay model is proposed.