before witnessing the mountain top, the poet (wrongly) assumes that 'the horizon's utmost boundary; far above, was nothing but the stars and the great sky'. In other words, he thinks the 'craggy ridge' is the much higher cliff face. The true shock, then, can be seen as one of self-realisation that the poet does not know everything - that his self-pride is misplaced, and there is much more to the world than he perceives.