If glaciers carry a mixture of different clast sizes, why are glacial outwash deposits layered?

Glacial outwash deposits layered because clasts fall out of the glacier in size progression. Glaciofluvial sediments are stratified deposits of sand and gravel, glacialy derived, but deposited by streams flowing from the glacier. Glaciolacustrine sediments are generally thinly layered, clay and silt-sized clasts carried by streams and deposited in quiet water.