SELECT AVG(elevation__ft_) FROM table_name_77 WHERE range = "unaka mountains" AND peak_name = "roan high bluff" AND isolation > 1.54
Berapa ketinggian Pegunungan Unaka, di Roan High Bluff Peak, dan isolasi lebih besar dari 1,54?
CREATE TABLE table_name_77 (elevation__ft_ INTEGER, isolation VARCHAR, range VARCHAR, peak_name VARCHAR)