before them in the west the world lay still , formless and grey ; but even as they looked , the shadows of night melted , the colours of the waking earth returned : green flowed over the wide meads of rohan ; the white mists shimmered in the watervales ; and far off to the left , thirty leagues or more , blue and purple stood the white mountains , rising into peaks of jet , tipped with glimmering snows , flushed with the rose of morning .