Page:Alaska days with John Muir.djvu/172

152 of prismatic colors when the sunlight struck them. As I gazed I could see the whole upper part of the cliff slowly moving forward until the ice-face was vertical. Then, foot by foot it would be pushed out until the upper edge overhung the water. Now the outer part, denuded of the ice powder, would present a face of delicate blue with darker shades where the mountain peaks cast their shadows. Suddenly from top to bottom of the ice cliff two deep lines of prussian blue appeared. They were crevasses made by the ice current flowing more rapidly in the center of the stream. Fascinated, I watched this great pyramid of blue-veined onyx lean forward until it became a tower of Pisa, with fragments falling thick and fast from its upper apex and from the cliffs out of which it had been split. Breathless and anxious, I awaited