 The crystal structure inside the pumice are larger than those outside, indicating that significant mechanical breakage during the eruption in which they were deposited.The exposed part of this layer is located around the southern base of the main caldera, and is colored ochre (light orange) on the diagram.The Seelys formation, next in the order, consists of lithic tuff and pumice-littered lithic lapilli-tuffs, banded, pumiceous, crystal tuff, and densely welded crystal tuff.