The amount of crossover between the AC chart and the Hot 100 has varied based on how much the passing pop music trends of the times appealed to adult listeners. Not many disco or new wave songs were particularly successful on the AC chart during the late 1970s and early 1980s, and much of the hip-hop and harder rock music featured on CHR formats later in the decade would have been unacceptable on AC radio.

Answer this question, if possible (if impossible, reply "unanswerable"): What genres, featured on the CHR radio format, were rarely found on adult contemporary radio?
hip-hop and harder rock music