The following is the commentary on the photo taken from Phaidon's The Photo Book. I particularly like the way the commentator interweaves allegorical and literal interpretation, grounding this even in the intention of the photographer!
This picture, of the stairs leading to the Chapter House in Wells Cathedral, was always meant to be understood in terms other than purely architectural ones. The steps themselves ripple and look increasingly like waves building in an ocean as they mount towards the lighted space beyond. The stairs seen rising to the right could be a great wave on the point of breaking, thus representing a danger to the traveller or pilgrim. In the middle is a cut block of stone, symbolizing a steadfast soul put in place by the Divine Architect. The point, though, is not just that the steps look oceanic but that they have been worn that way by generations of use, until their significance had been inscribed into the very fabric of the building. Evan's tendency was always to look for a meaning already present, making him very respectful of appearances as given and thus an early advocate of 'straight' photography (142; emphasis mine).For details of this photo go here. For other images by Frederick Evans, go here.