Whilst exploring the glacier in McCarthy, Alaska Mike and I searched long and hard for good looking natural features such as moulins. Moulins are the huge icy holes that the surface flow drop down in to. Some are small, some are huge, so deep that they eventually flow beneath the glacier itself. You do not want to slip in to a moulin!
The small dirt coated pyramidal features you see are solid, clear ice pyramids. There seems to be no rhyme or reason as to their formation, but they only seemed to be located close to the flowing water.